Should the HPV Vaccine Be Recommended for Boys and Young Men?

From Medscape Infectious Diseases > Offit on Vaccines

Paul A. Offit, MD

for audio go to - http://www.medscape.com/viewarticle/739017?src=mp&spon=9

Hi. My name is Paul Offit, and I'm talking to you today from the Division of Infectious Diseases at the Children's Hospital of Philadelphia.
What I thought we could talk about is something that's going to be coming up soon at the June Advisory Committee for Immunization Practices (ACIP) meeting at the Centers for Disease Control, which is whether to make the HPV, or human papillomavirus vaccine a routine recommendation for boys and young men. We'll see what happens, but there are certainly a few reasons that one could do that.

Let's go back to the beginning though.
The first HPV vaccine, which contained types 6, 11, 16, and 18, was licensed in the United States in June 2006.
Another vaccine was licensed 2 years later that contained types 16 and 18.
Now, 16 and 18 prevent cervical cancer in girls and prevent about 70% of those strains that do cause cervical cancer.
Types 6 and 11 would prevent about 90% of the strains that cause anal and genital warts.

So we'll see what comes up in this June meeting, but I would argue that there are 3 reasons for why this vaccine should be routinely recommended for boys and young men.
One is that boys and young men get anal and genital warts, and there are hundreds of thousands of cases every year of those warts.Although they aren't fatal, they certainly are emotionally crippling and disfiguring.
The second reason is that boys and young men get anal and genital cancers. There are several thousand cancers every year, both anal and genital cancers, as well as head and neck cancers that could be prevented by an HPV vaccine.
The third reason is that girls get HPV from boys, so at the very least, there's social responsibility to protect girls from getting that disease, which is really the reason that we recommend the rubella vaccine (ie, the German measles vaccine) for boys as well.
I think these are certainly very compelling reasons to make the HPV vaccine a routine recommendation for boys and young men.

Rear seats for kids

From Reuters Health Information

By Frederik Joelving

NEW YORK (Reuters Health) Mar 21 - Kids should sit in rear-facing car seats as long as they fit into them, or until age two, pediatricians urged Monday.

After that, they should ride in booster seats up to age eight or if they're still too small to fit correctly in seat belts.

"The best possible thing you can do is keep your child rear-facing as long as possible," said Dr. Benjamin Hoffman of the American Academy of Pediatrics, which issued the policy statement.
"We hope we will be able to convince parents to keep their children rear-facing longer."

The new recommendations update a 2002 statement, which had advised parents to follow car seat manufacturer limits, but also mentioned one year and 20 pounds as a minimum.

That led to some confusion among some parents, who would use the one-year cut-off as a milestone for when to make their child ride forward-facing, Dr. Hoffman told Reuters Health.

"The message, while it's been consistent, has not been as clear as it could have been for parents," he added.

According to the new statement, published online in Pediatrics, 1,500 kids under 16 die every year in car crashes in the U.S.

Child safety seats have been shown to cut the risk of death by 28% compared with seatbelts, and they also reduce non-fatal injuries.

That's because they distribute the energy of a collision over a bigger area, instead of concentrating it on the points where the seatbelt touches the body -- the shoulders, the belly and the hips.

Specifically, the AAP recommends:

- Infants should ride in rear-facing car safety seats until age two or until they reach the height and weight limits specified by the manufacturer.

- After that, they should ride in forward-facing car seats with a harness until age four or until they have outgrown the seat.

- Then they should be switched to a belt-positioning booster seat until they can use the seatbelt alone (typically between eight and 12 years, or when they've reached 4 feet 9 inches).

- Kids who are big enough to use the seatbelt alone should sit in the rear of the car until age 13.

The complete guidelines can be downloaded as a pdf file, at the URL given below.

SOURCE: http://bit.ly/hpFWdm

Pediatrics 2011.

Radiation From Japan's Nuclear Plant Now Poses Health Risk

From Medscape Medical News

Zosia Chustecka

March 15, 2011 — A third explosion at the Japanese nuclear plant damaged by the earthquake and tsunami, as well as a fire at another reactor, has resulted in fresh release of radiation that is now considered to be harmful and has increased fears over a catastrophic meltdown.

Radiation levels around the Fukushima Daiichi plant rose to 8 times the legal limit, according to the Tokyo Electric Power Company (TEPCO) as reported by BBC News. After the third explosion (on Tuesday morning in Japan), the radiation reading rose to 8217 microsieverts an hour, having stood at 1941 just an hour earlier. The annual legal limit is 1000 microsieverts.

"Now we are talking about levels that can damage human health," said Japan's Chief Cabinet Secretary Yukio Edano. He instructed local residents to stay indoors and make their homes airtight.

The exclusion zone around the Fukushima Daiichi nuclear plant has been increased again, this time to a radius of 19 miles (up from 12 miles yesterday, after the second explosion). In addition, around 800 workers at the plant have been evacuated, with only 50 workers now remaining.

The spike in radiation released after this latest explosion, in the third reactor that was operational when the earthquake and tsunami struck on March 11, has led to fears that this time there has been damage to the reactor containment vessels that houses the nuclear fuel rods.

Unlike in the previous 2 explosions at 2 other similar reactors, this time the roof did not blow off, and it is thought that the trapped pressure cracked the containment vessel around the reactor's core, allowing radioactive material to seep out, according to an ABC News Report.

High Risk of More Radiation

The Japanese government has not commented on the state of this containment vessel, but in a nationally televised address, Prime Minister Naoto Kan warned, "There is still a very high risk of more radiation coming out."

Other reports from Japan say that radiation levels have varied wildly. A Reuters report of a briefing given by TEPCO and the Japanese government on Tuesday, after the third explosion, noted that radiation levels as high as 400,000 microsieverts (400 millisieverts) an hour were measured at some places within the plant complex.

The radiation levels of up to 400 millisieverts per hour recorded at the Fukushima plant "are levels that you have to take very seriously indeed to ensure you avoid immediate health effects," Professor Richard Wakeford, PhD, from the Dalton Nuclear Institute at the University of Manchester, United Kingdom, told the BBC World Service. He said that Japanese authorities will be imposing a ban on food and drink from the area and issuing potassium iodide tablets to block the intake of radioactive iodine to the thyroid. In fact, even before the latest explosion took place, potassium iodide was being distributed by the Japanese government.

In addition to the third explosion, there has been a fire at another reactor (reactor number 4), which was operational when the earthquake struck because it was undergoing maintenance. The fire occurred in that reactor's cooling pool, where the spent nuclear fuel is stored. TEPCO said that pool may still be boiling and the water levels may be falling, but it cannot check at the sites or determine what has burned because radioactivity at the cooling pool is high. Radiation leakage from the complex is likely to spread, the company warned.

According to a report from the Associated Press, the incidents at the nuclear plant to date have injured 15 workers and military personnel and exposed up to 190 people to elevated levels of radiation.

That report also quoted Chief Cabinet Secretary Yukio Edano as saying that fuel rods appear to be melting in all 3 of the reactors that were operational when the earthquake struck — all 3 of which have since exploded.

"Although we cannot directly check it, it's highly likely happening," he said.

This has increased fears of the nightmare scenario of a meltdown, which would trigger a massive build-up of pressure inside the containment units. If they then crack, radioactive dusts and gas would spew out into the air.

However, the latest reports from Japan (as of noon EST) are that radiation levels have fallen around the Fukushima Daiichi nuclear plant.

International Atomic Energy Agency "Remains Concerned"

The International Atomic Energy Agency says it "remains concerned" over the status of the Fukushima Daiichi nuclear power plant. Workers are continuing to inject seawater into all 3 reactors to cool them, and attempts to return power to the site are ongoing.

After the explosions at reactors 1 and 3, the primary containment vessels of both units were reported to be intact. However, the third explosion in reactor 2 may have affected the integrity of its primary containment vessels, the IAEA said in a statement.

The agency also notes that iodide tablets have been distributed to people at evacuation centers, but no decision has been taken yet about their administration.

Worst-Case Scenario

Whether radiation exposure becomes a major risk depends fundamentally on what happens to the 3 reactors at Fukushima Daiichi, commented Nathan Hultman, PhD, an energy policy expert and assistant professor at the University of Maryland School of Public Policy, College Park.

"All 3 of these reactors are suspected of having at least a partial meltdown, and therefore stabilizing them will require at minimum a venting of radioactive steam," he said. "The worse the meltdown has been the higher the radiation levels in the steam."

"This is at least moderate concern," Dr. Hultman said. "A full core meltdown would be far more worrisome, leading to molten fuel in the bottom of the containment unit and increasing the likelihood of highly radioactive substances escaping."

"The worst case scenario is if such molten material would breach the containment unit en masse," he commented. "The containment vessels are designed to withstand this scenario, and if we were to face a complete meltdown, we can only hope that they were well built and not damaged by the earthquake."

Radiation Risks of Reactor Meltdown Both Short and Long Term

From Medscape Medical News

Robert Lowes

March 14, 2011 — The distribution of potassium iodide tablets in northern Japan underlines the fear of a catastrophic meltdown at the Fukushima Daiichi nuclear plant and the massive dispersion of deadly radioactive materials, with health implications for not only that country but also its neighbors.

Earlier in the crisis, radiation emitted by the plant's 3 overheating reactors was said to be at low, nonhazardous levels. However, radiation levels would skyrocket if the nuclear fuel in any of the reactors manages to escape its thick steel container. That possibility further worried Japanese authorities Monday evening EDT (Tuesday morning in Japan) when an explosion rocked reactor 2, the last of the units to blow. Kyodo News of Japan reported a spike in radiation, raising suspicions of a container breach.

"Each reactor has the radioactivity of 1000 Hiroshima bombs," said Ira Helfand, MD, an expert on radiation exposure in Leeds, Massachusetts, and a board member of the group Physicians for Social Responsibility, referring to the atomic bomb dropped on Hiroshima, Japan, during World War II.

The potassium iodide tablets were given out as protection against iodine-131, a radioisotope of iodine that can cause thyroid cancer. Iodine normally accumulates in the thyroid, so saturating the organ with a safe version by means of the tablets blocks the uptake of the radioactive version.

However, a busted nuclear reactor can throw off other dangerous particles, each with its own adverse effects on the body, Dr. Helfand told Medscape Medical News. "Strontium-90 is absorbed by bone, which leads to bone cancer and leukemia," he said. "Cesium-137 spreads throughout the body but favors muscle tissue. Plutonium is primarily toxic when inhaled and causes lung cancer."

Each particle’s half-life also calibrates risk. For iodine-131, it is a mercifully short 8 days; for strontium-90, it is an agonizingly long 29 years.

Symptoms of Acute Radiation Syndrome Subside, Return

In addition to long-term risks such as cancer, radioactivity can pose short-term risks. When most or all of the human body is exposed to a massive dose of radiation in a matter of minutes — a possibility with a nuclear reactor meltdown — the result is acute radiation syndrome (ARS).

The first symptoms of ARS — typically nausea, vomiting, and diarrhea — hit immediately, subside, and then come back strong, accompanied by loss of appetite, fatigue, fever, and possibly seizures and coma. Most people who do not recover die within several months, according to the US Centers for Disease Control and Prevention. In most cases, death results from the destruction of bone marrow, which leads to infections and internal bleeding.

A corollary to ARS is acute radiation damage to the skin, or cutaneous radiation injury (CRI). Symptoms such as transient itching, tingling, erythema, or edema can emerge within hours, days, or week. As with ARS, people with CRI usually experience a latent period of weeks to months. When skin lesions return, they can be debilitating or even life-threatening.

Shifting Winds a Factor

As a precaution, Japanese authorities have evacuated roughly 180,000 people from towns near the Fukushima Daiichi nuclear plant, even though radiation levels outside it as of Monday afternoon EDT were thousands of times below those considered dangerous. Japan also has benefited from westerly winds that have blown the small amounts of radioactive material east toward the Pacific Ocean. That drifting contamination does not pose a health threat to Hawaii, Alaska, or the West Coast, given the thousands of miles between Japan and the United States, according to the US Nuclear Regulatory Commission.

Rick Morin, PhD, chair of the safety committee of the American College of Radiology, explained that airborne radioactive material from the Japanese reactors is like smoke from a smokestack, diffusing and becoming less harmful the farther it travels. Traveling eastward, much of it would fall into the sea.

However, weather forecasts predict that winds in northern Japan will reverse direction tomorrow, which means any radioactive material from the reactors would be blown inland.

If a reactor meltdown spewed enormous quantities of radioactive particles in that weather scenario, Japan would have to worry about it coming down to earth and poisoning the food chain. Dr. Morin said thyroid cancer broke out among children after the meltdown of the nuclear reactor in Chernobyl, Ukraine, because they drank milk from cows that had eaten grass contaminated with iodine-131.

American Red Cross response to "Triangle of Life"

Rocky Lopes, PhD
Manager, Community Disaster Education
American Red Cross National Headquarters

Recently it has been brought to my attention that an email from Doug Copp, titled "Triangle of Life," is making its rounds again on the Internet. "Drop, Cover, and Hold On" is CORRECT, accurate, and APPROPRIATE for use in the United States for Earthquake safety. Mr. Copp's assertions in his message that everyone is always crushed if they get under something is incorrect.

Recently, the American Red Cross became aware of a challenge to the earthquake safety advice "Drop, Cover, and Hold On." This is according to information from Mr. Doug Copp, the Rescue Chief and Disaster Manager of American Rescue Team International (a private company not affiliated with the U.S. Government or other agency.) He says that going underneath objects during an earthquake [as in children being told to get under their desks at school] is very dangerous, and fatal should the building collapse in a strong earthquake. He also states that "everyone who gets under a doorway when a building collapses is killed." He further states that "if you are in bed when an earthquake happens, to roll out of bed next to it," and he also says that "If an earthquake happens while you are watching television and you cannot easily escape by getting out the door or window, then lie down and curl up in the fetal position next to a sofa, or large chair."

These recommendations are inaccurate for application in the United States and inconsistent with information developed through earthquake research.
Mr. Copp based his statements on observations of damage to buildings after an earthquake in Turkey. It is like "apples and oranges" to compare building construction standards, techniques, engineering principles, and construction materials between Turkey and the United States.

We at the American Red Cross have studied the research on the topic of earthquake safety for many years. We have benefited from extensive research done by the California Office of Emergency Services, California Seismic Safety Commission, professional and academic research organizations, and emergency management agencies, who have also studied the recommendation to "drop, cover, and hold on!" during the shaking of an earthquake. Personally, I have also benefited from those who preceded me in doing earthquake education in California since the Field Act was passed in 1933.

What the claims made by Mr. Copp of ARTI, Inc., does not seem to distinguish is that the recommendation to "drop, cover, and hold on!" is a U.S.-based recommendation based on U.S. Building Codes and construction standards. Much research in the United States has confirmed that "Drop, Cover, and Hold On!" has saved lives in the United States. Engineering researchers have demonstrated that very few buildings collapse or "pancake" in the U.S. as they might do in other countries. Using a web site to show one picture of one U.S. building that had a partial collapse after a major quake in an area with thousands of buildings that did not collapse during the same quake is inappropriate and misleading.

According to the Centers for Disease Control and Prevention (CDC), which collects data on injuries and deaths from all reportable causes in the U.S., as well as data from three University-based studies performed after the Loma Prieta (September, 1989) and Northridge (January, 1994) earthquakes in California, the following data are indicated: Loma Prieta: 63 deaths, approximately 3,700 people were injured. Most injuries happened as a result of the collapse of the Cypress Street section of I-880 in Oakland. Northridge: 57 deaths, 1,500 serious injuries. Most injuries were from falls caused by people trying to get out of their homes, or serious cuts and broken bones when people ran, barefooted, over broken glass (the earthquake happened in the early morning on a federal holiday when many people were still in bed.) There were millions of people in each of these earthquake-affected areas, and of those millions, many of them reported to have "dropped, covered, and held on" during the shaking of the earthquake.

We contend that "Drop, Cover, and Hold On" indeed SAVED lives, not killed people. Because the research continues to demonstrate that, in the U.S., "Drop, Cover, and Hold On!" works, the American Red Cross remains behind that recommendation. It is the simplest, reliable, and easiest method to teach people, including children.

The American Red Cross has not recommended use of a doorway for earthquake protection for more than a decade. The problem is that many doorways are not built into the structural integrity of a building, and may not offer protection. Also, simply put, doorways are not suitable for more than one person at a time.

The Red Cross, remaining consistent with the information published in "Talking About Disaster: Guide for Standard Messages," (visit http://www.disastereducation.org/guide.html ) states that if you are in bed when an earthquake happens, remain there. Rolling out of bed may lead to being injured by debris on the floor next to the bed. If you have done a good job of earthquake mitigation (that is, removing pictures or mirrors that could fall on a bed; anchoring tall bedroom furniture to wall studs, and the like), then you are safer to stay in bed rather than roll out of it during the shaking of an earthquake.

Also, the Red Cross strongly advises not try to move (that is, escape) during the shaking of an earthquake. The more and the longer distance that someone tries to move, the more likely they are to become injured by falling or flying debris, or by tripping, falling, or getting cut by damaged floors, walls, and items in the path of escape. Identifying potential "void areas" and planning on using them for earthquake protection is more difficult to teach, and hard to remember for people who are not educated in earthquake engineering principles.
The Red Cross is not saying that identifying potential voids is wrong or inappropriate.
What we are saying is that "Drop, Cover, and Hold On!" is NOT wrong -- in the United States. The American Red Cross, being a U.S.-based organization, does not extend its recommendations to apply in other countries.
What works here may not work elsewhere, so there is no dispute that the "void identification method" or the "Triangle of Life" may indeed be the best thing to teach in other countries where the risk of building collapse, even in moderate earthquakes, is great.

What to Do During an Earthquake

from Federal Emergency Management Agency
U.S. Department of Homeland Security

Stay as safe as possible during an earthquake. Be aware that some earthquakes are actually foreshocks and a larger earthquake might occur. Minimize your movements to a few steps to a nearby safe place and if you are indoors, stay there until the shaking has stopped and you are sure exiting is safe.
If indoors

* DROP to the ground; take COVER by getting under a sturdy table or other piece of furniture; and HOLD ON until the shaking stops. If there isn’t a table or desk near you, cover your face and head with your arms and crouch in an inside corner of the building.
* Stay away from glass, windows, outside doors and walls, and anything that could fall, such as lighting fixtures or furniture.
* Stay in bed if you are there when the earthquake strikes. Hold on and protect your head with a pillow, unless you are under a heavy light fixture that could fall. In that case, move to the nearest safe place.
* Use a doorway for shelter only if it is in close proximity to you and if you know it is a strongly supported, loadbearing doorway.
* Stay inside until the shaking stops and it is safe to go outside. Research has shown that most injuries occur when people inside buildings attempt to move to a different location inside the building or try to leave.
* Be aware that the electricity may go out or the sprinkler systems or fire alarms may turn on.
* DO NOT use the elevators.

If outdoors

* Stay there.
* Move away from buildings, streetlights, and utility wires.
* Once in the open, stay there until the shaking stops. The greatest danger exists directly outside buildings, at exits and alongside exterior walls. Many of the 120 fatalities from the 1933 Long Beach earthquake occurred when people ran outside of buildings only to be killed by falling debris from collapsing walls. Ground movement during an earthquake is seldom the direct cause of death or injury. Most earthquake-related casualties result from collapsing walls, flying glass, and falling objects.

If in a moving vehicle

* Stop as quickly as safety permits and stay in the vehicle. Avoid stopping near or under buildings, trees, overpasses, and utility wires.
* Proceed cautiously once the earthquake has stopped. Avoid roads, bridges, or ramps that might have been damaged by the earthquake.

If trapped under debris

* Do not light a match.
* Do not move about or kick up dust.
* Cover your mouth with a handkerchief or clothing.
* Tap on a pipe or wall so rescuers can locate you. Use a whistle if one is available. Shout only as a last resort. Shouting can cause you to inhale dangerous amounts of dust.

Last Modified: Wednesday, 11-Aug-2010 14:41:22 EDT
http://www.fema.gov/hazard/earthquake/eq_during.shtm

Earthquake Triangle of Life

http://en.wikipedia.org/wiki/Triangle_of_Life

The Triangle of Life is a controversial theory about how to survive a major earthquake, typically promoted via viral emails.

The theory advocated methods of protection very different from the mainstream advice of "drop, cover, and hold on" method widely supported by reputable agencies. In particular, the method's developer and key proponent, Doug Copp, recommends that at the onset of a major earthquake, building occupants should seek shelter near solid items that will provide a protective space, a void or space that could prevent injury or permit survival in the event of a major structural failure, a "pancake collapse", and specifiably advises against sheltering under tables.

Officials of many agencies have found themselves forced to respond to these viral emails spreading the "Triangle of Life" method.

Theory

According to Copp's theory, when buildings collapse, the weight of the ceilings falling upon the objects or furniture inside tends to crush them, but the height of the object that remains acts as a kind of roof beam over the space or void next to it, which will tend to end up with a sloping roof over it.
This space for survival Copp terms the triangle of life.
The larger and stronger the object, the less it will compact; the less it compacts, the larger the void next to it will be. Such triangles are the most common shape to be found in a collapsed building.

Criticisms of theory

According to United States Geological Survey, the Triangle of Life is a misguided idea about the best location a person should try to occupy during an earthquake. Critics have argued that it is actually very difficult to know where these triangles will be formed, as objects (including large, heavy objects) often move around during earthquakes. It is also argued that this movement means that lying beside heavy objects is very dangerous.
Statistical studies of earthquake deaths show most injuries/deaths occur due to falling objects, not structures.
Also, given that there are no warnings for earthquakes, you are more likely to be injured trying to move during an earthquake rather than immediately seeking a doorway, furniture, or near an interior wall. This strategy, combined with good engineering and educated search and rescue teams is the safest.
The Triangle of Life theory encourages individuals to put themselves at far higher risk by seeking safe zones which they are unlikely to reach.

Mahdavifar et al. (2010) analyzed and compared both methods in detail, considering their application, the extent of people who are under the coverage, simplicity in transferring concepts, and the probability of reducing casualties and damage in developing countries such as Iran.

Based on the results and observations, they concluded that duck and cover is still regarded as a better option for people during an earthquake.

Testing

In 1996, Copp claims to have made a film to prove this methodology and to have recreated a model school and home, filling them with 20 mannequins. However Marla Petal, a critic of Copp, has stated that this was a rescue exercise rather than an experiment as claimed by Copp, and because it did not simulate the lateral movement of earthquakes, the results are highly misleading.

The buildings were collapsed by earthmoving equipment that knocked the supporting pillars out. Half the mannequins were in 'duck and cover' positions and the others in what Copp calls the 'triangle of life' positions. When Copp and his crew re-entered the building after the blast, they calculated that there would have been no survivors amongst the mannequins in 'duck and cover' positions, as against 100% survival for those hiding in the triangles beside solid objects. Copp is categorical about the importance of this technique, saying "Everyone who simply ducks and covers when buildings collapse is crushed to death - every time without exception."
Petal disputes this on the exercise did not simulate the lateral motion of an earthquake, but instead they induced a pancake collapse which is rare in developed countries. However these collapses can occur in areas of extremely poor construction.

References

1. ^ "What to Do During an Earthquake", Federal Emergency Management Agency website
2. ^ "Drop, Cover, and Hold On!", Southern California Earthquake Center
3. ^ "DROP, COVER, AND HOLD ON! " Alaskan Red Cross
4. ^ "Drop, cover and hold still the best advice", New Zealand government website
5. ^ "DROP, COVER, AND HOLD ON! ", www.shropshire.gov.uk
6. ^ "protect yourself from falling debris by hiding under a strong table or structure", United Nations Educational, Scientific and Cultural Organization
7. ^ "Discredited earthquake safety advice circulated", Press Release: National Crisis Management Centre
8. ^ http://www.caymannetnews.com/article.php?news_id=19996 "'Safe practice' urged for earthquake preparedness"], Hazard Management Cayman Islands (HMCI) spokesperson
9. ^ "ODPEM dismisses quake tips from Doug Copp", JAMAICA'S Office of Disaster Preparedness and Emergency Management
10. ^ http://earthquake.usgs.gov/learn/faq/?categoryID=6&faqID=141 USGS - Common Myths about Earthquakes
11. ^ a b c d Douglas Copp - Worse than urban legend: dangerous advice! and now for some good advice for earthquake safety by Marla Petal, Ph.D. is Director of Bogaziçi University, Kandilli Observatory and Earthquake Research Institute's Disaster Preparedness Education Program.
12. ^ Mahdavifar, M., Izadkhah, Y.O., Heshmati, V. 2010. "Appropriate and Correct Reactions during Earthquakes: “Drop, Cover and Hold on” or “Triangle of Life”"; Journal of Seismology and Earthquake Engineering, Vol. 11, No. 1.
13. ^ Copp, Doug. "American Rescue Team Survival Magazine Article". The American Rescue Team International. http://www.amerrescue.org/arti_survivalarticle.htm. Retrieved 2010-03-13.

Another Explosion at Stricken Japanese Nuclear Plant; Radiation Risk Is Low Zosia Chustecka

From Medscape Medical News

March 14, 2011 — Another explosion has hit the Japanese nuclear plant damaged by last Friday's earthquake and resultant tsunami, raising new fears about potential meltdown and radiation exposure.

Japanese prime minister Naoto Kan described the situation at the nuclear plant as "alarming" and said the earthquake has thrown Japan into "the most severe crisis since World War II."

The earthquake and tsunami on March 11 have wrought terrible destruction across northeast Japan, with tens of thousands of people missing and presumed dead. One town alone has officially listed more than 9500 missing — more than half of the total population of Minamisanriku. Situated on the coast nearest the epicenter of the earthquake, it was flattened by the tsunami, and only a few concrete structures, including the hospital, now remain standing.

Amid the devastation, there is increasing concern over a potential nuclear disaster, following explosions at the Fukushima Daiichi nuclear plant, also situated on the coast.

Damage from the earthquake and tsunami, as well as from aftershocks, have resulted in failure of automatic cooling systems, leading to a build-up of heat and hydrogen, escape of radioactive steam, resulting in explosions.

According to the Tokyo Electric Power Company's (TEPCO) Web site, the Fukushima Daiichi plant has 6 functioning nuclear reactors. However, reactors 4, 5, and 6 were down because of regular inspections. The 3 reactors that were operating were all shut down after the earthquake, but soon afterward the Japanese government announced a nuclear emergency because of a reactor cooling system malfunction at reactor 1.

Even when reactors are shut down safely, they have to be cooled constantly to avoid a meltdown of the core. "Reactors are not like your car that you can turn off and walk away. They're going to continue generating a great amount of heat until the core is disassembled," explained Ron Chesser, PhD, director of the Center for Environmental Radiation Studies at Texas Tech University in Lubbock. "Without cooling water, then you stand a real chance of a meltdown of core that could result in a large release of radiation, potentially."

Despite efforts to cool the reactor, including pumping in seawater, there was an explosion at reactor 1 on Saturday afternoon, and another at reactor 3 today. TEPCO said that 4 people were injured in the first explosion, and 7 in the latest explosion.

In addition, reactor 2 is also has problems with its cooling system: water levels are falling, and sea water is being pumped in, said Japan's Chief Cabinet Secretary Yukio Edano. These were the same problems that preceded the explosions in the other 2 reactors.

The area around the nuclear plants has been evacuated — initially to a radius of 1.9 miles, affecting 3000 people, but after the first explosion that was increased to a radius of 12 miles, affecting 140,000 local residents.

The fear is that there will be a release of radiation if the problems at the nuclear plant cannot be contained.

The Japanese government was reported to be distributing potassium iodide tablets to prevent radiation sickness. This is a standard procedure in the event of a nuclear alarm. Ingestion of potassium iodide saturates the body with a stable form of iodine and protects the thyroid gland from taking up radioactive iodine, which may be released in a nuclear accident.

Understandably, this is a highly sensitive issue in the only country in the world to have suffered from widespread radiation sickness after the atomic bombs fell on Hiroshima and Nagasaki.

So far, however, there has been limited release of radiation. At a news conference on Sunday, Edano dismissed worries that the radiation posed a public-health threat, according to an article published today in the English-speaking version of The Japan Times.
Dr. Michael Corradini

An emergency status is triggered when the radiation released per hour amounts to more than one tenth of the natural background radiation, explained Michael Corrandini, PhD, chair of engineering physics at the University of Wisconsin in Madison. Some radiation released on Friday after the earthquake reached this level, but since then the radiation levels have been decreasing continually, and the measurements are now below this trigger level, he said.

The radioactivity would have been released in steam escaping from the plant as the reactor was being cooled, he explained. This is part of the safety procedure, he continued, to vent the steam coming off the reactor into the building that surrounds it.

"The impression I get from reading the news reports is that they had a stoppage that allowed the coolant to fall to a level inside the reactor core such that the metal cladding of the core, which is made of zirconium, started to chemically react with the steam, which produced hydrogen," he told Medscape Medical News. Following safety procedures, they would have then vented the steam into the containment building, and the released hydrogen would have normally been inert, but it appears to have built up and ignited and that exploded, blowing off the top of the building, he said.

Dr. Corrandini emphasized that only the outer building was in the explosion. The nuclear material is in the reactor core, which is surrounded by metal cladding, and this is housed in a steel reactor vessel within a larger steel containment. "It's the building outside this containment that we see in the explosion," he said. The Japanese Nuclear and Industrial Safety Agency has made a point of emphasizing that the containment vessel is still intact, he noted.

These hydrogen combustion explosions "are not a disaster," Dr. Corrandini commented; what's gone is the "industrial building that keeps out the weather."

"That's not the safety issue," he said. "The issue is, has this promoted any radiation release, and the answer to that, as far as I can tell, is no."

From the reports both inside Japan and from measurements taken by US ships in nearby waters, the radiation release so far has been comparable to that seen in the 1979 disaster at Three Mile Island (TMI) in Pennsylvania, Dr. Corrandini commented.

In that incident, which involved a partial meltdown, there was also a venting of gases, and there was release of small amounts of radioactivity and radioactive iodine, but there have been no documented health consequences — there were no early effects, no genetic damage, and no latent cancers recorded in the 32 years since then, he pointed out.

"For me to say it's the same here [regarding Japan] is inappropriate, as we are only 3 days into this calamity, but as far as I can see from what I have read, they have the situation under control, and I would predict that the radiological consequences would be similar to that seen after TMI," he said.

"That's a million times less than after Chernobyl," Dr. Corrandini added, referring to the 1986 disaster at Chernobyl in the former USSR, which resulted in widespread release of radioactivity and documented adverse health consequences for years afterward, including cancers.

A Chernobyl-like disaster is not possible in this case, he emphasized — this is a totally different type of reactor with a different design.

"Some news reports have been very misleading and causing inappropriate amounts of concern by suggesting that this may lead to another Chernobyl-like disaster," he said. "It's fair and rational to inform the general public that there has been radiation release, and to ask questions about the health consequences about that...but we should be fair and rational about this."

The medical aid group Doctors Without Borders (Médicins sans Fronti`res) said that they are "closely monitoring the situation around Fukushima nuclear power plants. If there is a serious nuclear incident, it is only the Japanese government that will be in a position to react."

"The longer-term impact of the tsunami and the resulting nuclear problem cannot really be understood at present. However, there are international teams of experts on the scene and so the world's expertise is being brought to bear on this serious issue," commented Kirby Kemper, PhD, professor of physics at Florida State University in Tallahassee.

"To me, it will be another 3 days before the reactors are fully under control, and then the assessment can begin," he told Medscape Medical News.

CBRNE - Nuclear and Radiologic Decontamination

eMedicine Specialties > Emergency Medicine > Warfare - Chemical, Biological, Radiological, Nuclear and Explosives

Author: Scott D Weingart, MD, Assistant Clinical Professor and Director, Division of Emergency Department Critical Care, Department of Emergency Medicine, Mount Sinai School of Medicine
Coauthor(s): Ben R Maltz, MD, State Surgeon, Washington Army National Guard, Science Officer, 10th Civil Support Team (Weapons of Mass Destruction)

Updated: Mar 9, 2009

In light of the events of September 11, 2002, terrorist attack has moved to the forefront of emergency department (ED) and Emergency Medical Services (EMS) planning. The use of radiologic weaponry is one threat that must be considered. In addition to attack by terrorists, preparations must also be made for a nuclear power plant disaster or contamination by radiologic medical sources. In the event of radiologic contamination, rapid treatment can be lifesaving.

Properly completed, rapid decontamination can reduce morbidity and mortality, limit the spread of contamination, and keep the ED functioning for the treatment of other patients.

For related information, see CBRNE - Radiation Emergencies. For excellent patient education resources, visit eMedicine's Bioterrorism and Warfare Center. Also, see eMedicine's patient education article Chemical Warfare.

Recognition of Contamination

The first step of recognizing contamination is to understand the difference between exposure to and contamination by radiologic agents.
Exposure is defined by an individual's proximity to material emitting ionizing radiation.
Actually touching, inhaling, or swallowing that material is contamination.1

A useful analogy is to imagine a person sitting around a campfire. By merely sitting next to the fire, the individual is exposed to the heat. If the person sits close enough to the fire, he or she might even get burned; however, as soon as the person is removed from the proximity of the fire, he or she would certainly not burn anyone else. If the person falls into the fire, in addition to being burned, he or she becomes covered in ash. This is external contamination. If other people touch the individual who fell into the fire, they would get ash on their hands, spreading the contamination. In the course of falling into the fire, if the individual swallowed, inhaled, or absorbed any of the ashes through cut skin, he or she would be internally contaminated as well.
Personal Protective Equipment

For an isolated radiologic incident, level D personal protective equipment (PPE) is all that is required. Level D PPE consists of surgical gown, mask, and latex gloves (universal precautions). If airborne contamination is a possibility, the use of a fitted air-purifying respirator (N95 or 100 filter mask) increases protection. Eye protection should also be worn to prevent ocular contamination from any splashing during the decontamination procedure. If any possibility of mixed exposure exists, higher levels of PPE may be required as dictated by the chemical or biological agents involved (see CBRNE - Personal Protective Equipment). Local and state laws, facility protocols, and Occupational Safety and Health Administration (OSHA) regulations must be followed.2,3

Shielding devices that are normally used for radiology studies are not recommended for radiologic decontamination. These devices, such as lead aprons, were designed to block low-energy radionuclides and are not effective shields for the high-energy emissions present in most decontamination situations. In addition, their bulk hinders the decontamination process and therefore leads to an increased exposure time.

Shielding capacity is limited in the hospital environment. However, other factors may potentially limit exposure to those providing patient decontamination. These factors are time, distance, and quantity.
The longer the time spent in the contaminated environment, the greater the dose of radiation to the worker; therefore, a rotating team approach is advised. Doubling the distance from the radioactive source decreases the dose by a factor of 4. Likewise, limiting the quantity of radioactive items in the decontamination area is advisable.

External Decontamination

The process of external decontamination can be divided into 2 stages: gross decontamination and secondary decontamination.

Gross decontamination

Gross decontamination is usually performed before the patient reaches a hospital environment. It consists of removal of all the patient's clothing and, if possible, brief irrigation of the patient's entire body with water. Clothing should be removed with a careful "roll-down" method to prevent inhalation of airborne particulates. If the patient is contaminated solely by a radiologic source, water is sufficient for the washing. If a possibility of mixed contamination exists, the protocols for biologic and/or chemical decontamination should be used because these regimens are more extensive than those used for radiologic decontamination. Since most radiologic contamination is located on the head and hands, the patient should be in the "head-back" position during initial showering to prevent run-off into the eyes, nose, or mouth. Early handwashing is also important.

Gross decontamination removes more than 95% of external contamination and renders the patient safe for access by care providers.1 If gross decontamination has not occurred in the field, it must be performed by ED personnel in a designated decontamination site. In most centers, the decontamination site is outside and immediately adjacent to the ED. The small amount of radioactivity present in the irrigation runoff produces minimal risk to the communal water supply or groundwater; therefore, patient decontamination should not be delayed by attempts to contain run-off. However, facility protocols and local, state, and federal laws should always be followed. After gross decontamination, the patient should be wrapped in a sheet for transport into the ED.

If the patient requiring decontamination becomes medically unstable at any point during the process, provision of medical care should take precedence over decontamination. The risk to care providers when treating a patient with radiologic contamination is virtually nil. If available, a radiation survey meter can be used to identify the extremely rare case of a patient who is emitting an amount of radiation sufficient to cause concern.

In the event of a mass casualty incident, gross decontamination is all that is immediately necessary. Patients should disrobe, with assistance if necessary. If able to ambulate, patients can briefly shower in a decontamination area. Likewise, the decontamination team needs only water to briefly wash patients who are unable to shower themselves. At this point, patients are sufficiently decontaminated and can receive treatment of any medical problems. Secondary decontamination of these patients can be postponed until more resources are available.

Secondary decontamination

Secondary decontamination is a stepwise methodical cleansing of any remaining radioactive areas of the patient. It should be performed under the guidance of the hospital's Radiation Safety Officer (RSO) or another member of the team trained in the use of radiation detection devices (RDD), such as a radiac instrument.

An area in the ED should be set aside for the decontamination procedure. Because this area may be out of service for a significant period, a location should be chosen that would not interrupt the normal workings of the department. A path to the decontamination room should be made with paper floor coverings and clear barriers to prevent the spread of contamination. In addition, these barriers prevent the entrance of extraneous personnel and visitors.

A decontamination team customarily consists of the RSO and two assistants, one of whom may be a clinician. However, in a mass-casualty setting, clinicians will likely not be available to perform decontamination. All members of the team should change out of their normal clothing into attire that can be bagged after the procedure. Shoe coverings, surgical masks, and eye protection should also be worn. Each member should be issued a dosimeter, which is a device that passively measures exposure to radioisotopes.

The general procedure for secondary decontamination involves using an RDD to perform a head-to-toe survey of all areas of the patient's body. Further irrigation is required for any areas with readings above the threshold, which is determined by the RSO on the basis of the RDD calibration. All secretions and runoff should be collected for sampling and dose estimation. After irrigation, the areas are surveyed again. This process is continued until acceptable levels are reached. Acceptable levels may be slightly above baseline and should be determined by the RSO and treating physicians.

Certain areas of the body require special procedures, as follows:2

* Mouth: Remove and bag any dentures, loose dental work, or foreign bodies. Take swab samples from the oral cavity. Preferable sites for swabs are under the tongue and between gums and teeth. The patient or physician should gently brush the teeth, gums, and tongue, being careful to avoid irritating the gums and causing bleeding. The mouth should then be copiously rinsed, taking care to avoid swallowing the rinse water. Resample with the RDD as above.
* Nose: Obtain nasal swabs. The patient should then gently blow his or her nose. Irrigate the nares while the patient leans forward, taking care to prevent the irrigating solution from being swallowed or aspirated.
* Eyes: If no contraindications exist, anesthetize the eyes with a topical agent. Sample the conjunctiva with moistened swabs, and copiously irrigate with saline. This can be facilitated with commercial eye irrigation devices, or a nasal canula attached to an intravenous (IV) bag can be used as an improvised eye irrigation system. If irrigating manually, irrigate medial to lateral with the patient's head turned to the side to minimize contamination of the lacrimal duct.
* Ears: Take samples from the external canals with moistened swabs. Examine the tympanic membranes for perforation, especially after blast incidents. If no perforation is found, copiously irrigate the canals with saline warmed to body temperature.
* Open wounds: Obtain wound swabs. If any particulate matter or foreign bodies are present, they should be removed and saved. Copiously irrigate the area and resurvey as in intact skin. Cover the wound with waterproof dressing to avoid recontamination from the run-off from irrigating other areas.

Internal Decontamination

Internal decontamination can be achieved by a number of methods, including the blockade of enteral absorption, blockade of end-organ uptake, dilution, and chelation. Speed is of the essence because some isotopes can be incorporated by end organs within an hour of exposure and are very difficult to remove. Therefore, EDs that are expected to care for these individuals must have the resources for internal decontamination available.

Blockade of enteral absorption

Gastric lavage and emetic agents: Although these strategies may decrease absorption of radioisotopes if initiated early after gastric contamination, they also create the risk of aspiration of radioisotopes, leading to respiratory contamination. No studies using gastric lavage or emetic agents for radiologic decontamination have been performed. However, a comparison can possibly be made with toxicologic exposures in which there are few recommended uses for these procedures. The authors currently do not recommend the routine use of gastric lavage or emetic agents.

Enteral binding methods: Some enteral binding methods have been shown to effectively bind specific agents of contamination.4,2

* Barium sulfate: This drug, which is commonly used for radiographic contrast studies, forms irreversible bonds with strontium and radium, which are used in older military, industrial, and medical equipment. Once bound, these agents pass through the gastrointestinal tract unabsorbed. A 1-time dose of 200 mL of 100% barium sulfate should be administered for internal decontamination.
* Aluminum and magnesium salts: Commercially available in agents such as Maalox and Mylanta, these salts bind to and reduce the absorption of strontium, radium, and phosphorus in a manner similar to barium sulfate. A dose of 100 mL of either of these agents should be given by mouth or nasogastric tube as soon as possible after exposure.
* Prussian blue: This agent binds to and increases the elimination of cesium and thallium. Cesium is found in medical radiotherapy devices and was used by terrorists in Russia during an attempted attack; thallium is used in medical imaging. Prussian blue also blocks the absorption of rubidium. If internal contamination with one of these agents is present, administer 1 g by mouth tid for 3 weeks. This medication has recently received FDA approval under the name Radiogardase.
* Activated charcoal: In patients without a decreased level of consciousness, the administration of one dose of activated charcoal may bind to and speed the elimination of some radioisotopes. Because the adverse effects of this medication are rare, activated charcoal is recommended if administered shortly after exposure. A dose of 50-100 g should be given by mouth or gastric tube; if the patient is at risk for aspiration, this medication should be avoided.

Blockade of end-organ uptake

Potassium iodide (KI): This medication has recently received much attention by the press. It is viewed by the public as a universal blocking agent for all the effects of a radiologic or nuclear attack. Radioactive iodine (RAI) is present in nuclear reactor fuel rods; therefore, in the event of any reactor accident, terrorist attack, or use of fuel rods for terrorist explosive devices (radiation dispersal devices, ie, dirty bombs), RAI can be released. The primary toxicity of RAI is to the thyroid gland. Competitive blockade of RAI and technetium uptake can be achieved with large doses of KI. Effectiveness is directly proportional to the speed of administration, which is preferably within 6 hours of exposure. Toxicity of RAI is highest in the pediatric population, but this medication should be administered to any patient who has been contaminated. The dose is 300 mg/d by mouth for 1-2 weeks.

Calcium: Calcium gluconate or calcium chloride can be administered to limit the incorporation of strontium or radioactive calcium into bone. Patients can receive 1 g of calcium chloride or 3 g of calcium gluconate administered intravenously.

Dilution

Oral fluids: Tritium is present in nuclear weapons and is used by the military for luminescent gun sights. If internal contamination with tritium is suspected, administer copious oral or intravenous fluids to cause dilution and increase renal excretion of tritiated water. Oral fluid in the amount of 5-10 L/d should be administered for 1 week. Sodium monitoring is necessary if hypotonic fluids are used.

Phosphorus: Similar to dilution of tritium, oral loading with phosphorus salts (Neutra-Phos) can enhance the elimination of radioactive phosphorus. One packet of Neutra Phos or 2 tablets of K Phos should be administered qid by mouth for 3 days.

Chelation

Diethylenetriamine pentaacetic acid (DTPA): Americium (a daughter product of plutonium), uranium, plutonium, and other heavy metals (present in nuclear reactors and weapons) are poorly excreted by the kidneys. Pentetate calcium trisodium (CaDTPA) and pentetate zinc trisodium (ZnDTPA) form compounds with specific radioisotopes (ie, americium, curium, plutonium), rendering them more easily excreted by the kidneys and enhancing elimination. These drugs were recently FDA approved. The Oak Ridge Institute of Science and Education has given DTPA IND status. Immediately contact REAC/TS in the event of a contamination (see Obtaining Expert Advice).

If within the first 24 hours of exposure, use Ca-DTPA. For subsequent doses, or if first treating after 24 hours of exposure, use Zn-DTPA. The dose for either agent is 1 g dissolved in 250 mL of saline or D5W given over 1 hour qd. If the exposure is solely respiratory, 1 g of either agent can be mixed 1:1 with normal saline and nebulized.

Penicillamine: Radioactive cobalt is used for medical radiotherapy and food irradiation. In the case of internal contamination caused by radioactive cobalt, similar clinical effects to DTPA administration can be achieved with the use of penicillamine. The dose is 250-500 mg by mouth 4 times per day.

Decrease organ damage

Sodium bicarbonate: Depleted uranium is found in reactor fuel rods and nuclear weapons. It can cause acute tubular necrosis (ATN) and renal failure in cases of internal contamination. The alkalinization provided by sodium bicarbonate makes the uranium less nephrotoxic. Administer an initial bolus of 2 mEq/kg intravenously. Then add 4 ampules to 1 L of D5W and titrated to a urinary pH of 6.5-7.5. (Urinary acidification has been proposed to enhance the elimination of strontium.)

Wound excision

Wound excision may be considered when the wound is contaminated with an isotope that has a very long half-life, such as plutonium.
Obtaining Expert Advice

The treatment of patients with internal contamination involves complicated diagnostic and therapeutic regimens. In addition to the local poison center (nationwide number, 1-800-222-1222), one of the following agencies should be contacted for guidance as soon as possible.

* Armed Forces Radiobiology Research Institute (AFRRI) Web site; telephone, (301) 295-0530
* Radiation Emergency Assistance Center/Training Site (REAC/TS) Web site; telephone, (865) 576-1005 (ask for REAC/TS)

Obesity and Women's Health: An Evidence-based Review

From Journal of the American Board of Family Medicine

Teresa Kulie, MD; Andrew Slattengren, DO; Jackie Redmer, MD, MPH; Helen Counts, MD; Anne Eglash, MD; Sarina Schrager, MD, MS

Posted: 02/27/2011; J Am Board Fam Med. 2011;24(1):75-85. © 2011 American Board of Family Medicine

Abstract

Obesity negatively impacts the health of women in many ways.
Being overweight or obese increases the relative risk of diabetes and coronary artery disease in women.
Women who are obese have a higher risk of low back pain and knee osteoarthritis. Obesity negatively affects both contraception and fertility as well.
Maternal obesity is linked with higher rates of cesarean section as well as higher rates of high-risk obstetrical conditions such as diabetes and hypertension. Pregnancy outcomes are negatively affected by maternal obesity (increased risk of neonatal mortality and malformations).
Maternal obesity is associated with a decreased intention to breastfeed, decreased initiation of breastfeeding, and decreased duration of breastfeeding.
There seems to be an association between obesity and depression in women, though cultural factors may influence this association.
Obese women are at higher risk for multiple cancers, including endometrial cancer, cervical cancer, breast cancer, and perhaps ovarian cancer.

Introduction

The prevalence of obesity is rising.
The World Health Organization estimates that more than 1 billion people are overweight, with 300 million meeting the criteria for obesity.
Twenty-six percent of nonpregnant women ages 20 to 39 are overweight and 29% are obese.
This article will review the wide-ranging effects that obesity has on both reproductive health and chronic medical conditions in women.

A PubMed search was performed using the key words "obesity," "overweight," "body mass index" (BMI), "gender," "women's health," and the condition reviewed.
The most recent evidence-based articles were included in the review.
The evidence level of each article was determined by the authors based on the type of study, randomization, the number of participants, and loss to follow-up.

Table 1 provides a classification for overweight and obesity based on BMI.
Waist circumference can also be used to classify overweight and obesity.
In women, a waist circumference of >35 inches (88 cm) is high risk, whereas in men the level is >40 inches (102 cm).
Research varies in the measurements of obesity used to classify participants in each study.

Obesity and Type 2 Diabetes Mellitus

The risk of diabetes mellitus (DM) increases with the degree and duration of being overweight or obese and with a more central or visceral distribution of body fat. Increased visceral fat enhances the degree of insulin resistance associated with obesity.
In turn, insulin resistance and increased visceral fat are the hallmarks of metabolic syndrome, an assembly of risk factors for developing diabetes and cardiovascular disease.

The Nurses' Health Study followed 84,000 female nurses for 16 years and found that being overweight or obese was the single most important predictor of DM.
An increased risk of DM was seen in women with BMI values >24 and a waist-to-hip ratio >0.76.
After adjusting for age, family history of diabetes, smoking, exercise, and several dietary factors, the relative risk (RR) of DM for the 90th percentile (BMI = 29.9) versus the 10th percentile (BMI = 20.1) was 11.2 (95% CI, 7.9–15.9). A recent meta-analysis similarly found a pooled RR for developing DM of 12.41 (95% CI, 9.03–17.06) among obese women.

In morbidly obese patients (BMI >40 or >35 with major comorbidities), weight loss surgery can be considered if conservative measures fail.
In one Swedish study, 68% of obese patients with DM who underwent gastric bypass surgery and subsequently lost weight went into remission.A systematic review that included more than 135,000 patients (80% women) found that bariatric surgery resulted in complete resolution of diabetes in 78% of patients and improvement in diabetic control in more than 86% of patients. These patients had improvements in insulin levels, fasting glucose levels, and glycosylated hemoglobin levels.

Obesity and Coronary Artery Disease

Obesity is an independent risk factor for the development of coronary artery disease (CAD) in women and is an important modifiable risk factor for prevention of CAD. The mechanism of action is likely the relationship between obesity and insulin resistance. In a large cohort study of 37,000 women in Washington state, women with a BMI ≥35 had an odds ratio (OR) of 2.7 for CAD and an OR of 5.4 for hypertension.

Abdominal obesity may be more harmful in women than BMI or weight alone.
Waist circumference is an independent risk factor for developing CAD in both normal-weight women and overweight women.The Interheart global case-control study of 6787 women from 52 countries found that abdominal obesity was more predictive of myocardial infarction than was BMI alone.
A prospective cohort study of more than 44,000 women in the Nurses Health Study found an association between having a waist circumference of >88 cm and the risk of cardiovascular mortality. Women with a waist circumference of >88 cm had a RR of death from cardiovascular disease of 3.02 (95% CI, 1.31–6.99).
Waist-to-hip ratio is another significant predictor of death from cardiovascular disease, with a RR of 3.45 (95% CI, 2.02 to 6.92) in women with a ratio of >0.88.

A meta-analysis that included data on more than 22,000 patients (72% women) looking at the relationship between bariatric surgery and cardiovascular risk factors found that hyperlipidemia improved in 70% of patients after surgery and hypertension was resolved in 62% and improved in 78%.

Obesity and Musculoskeletal Pain

In the United States, the Center for Disease Control and Prevention statistics show that more than 31% of obese adults reported a doctor diagnosis of arthritis compared with only 16% of nonobese adults.Obesity has been implicated in the development or progression of low back pain and knee osteoarthritis (OA) in women.

The mechanism by which obesity causes lumbar back pain is poorly understood, but the contribution of both mechanical and system factors is likely. Direct mechanical stress on the intervertebral discs and the indirect effects of atherosclerosis on blood flow to the lumbar spine are suspected to be mechanisms through which obesity affects the discs, leading to subsequent low back pain. Further research to elucidate the exact mechanism is needed.

Obesity at age 23 increases the risk of low back pain onset for women within 10 years[19] (Table 2). The increased burden of obesity is more obvious as women age, with significantly more obese women over the age of 40 reporting low back pain and lumbosacral radicular symptoms.[23] These symptoms increase further in obese women over the age of 54.[24] This data supports the theory that obesity over time contributes to low back pain and that weight loss may help prevent the onset of low back pain in obese women. There is no evidence to support the recommendation of weight loss to treat low back pain once the pain is present.

The data supporting the link between obesity and knee OA in women is even more staggering. The factors underlying the association of obesity with knee OA have not been entirely elucidated. Obesity leads to an excess load on the joint, increased cartilage turnover, increased collagen type 2 degradation products, and increased risk of degenerative meniscal lesions. Although all of these have been theorized to lead to knee OA no causal relationships have been demonstrated to date.[25,26]

Studies have shown that women with a diagnosis of knee OA have an average BMI that is 24% higher than women without OA.For every 2 units of BMI gain, the risk of knee OA increases by 36%,and 1 category shift downward in BMI from obese to overweight may avoid 19% of new cases of severe knee pain (Table 3). The importance of prevention of knee OA is highlighted by the subsequent burden of surgery. An estimated 69% of knee replacements in middle-aged women in the United Kingdom have been attributable to obesity. Dietary weight loss in combination with exercise effectively led to significant improvements in pain and physical function in women with knee OA over 18 months in the Arthritis, Diet, and Activity Promotion Trial.A separate, randomized clinical trial evaluating rapid weight loss found that a 10% weight reduction improved function by 28%, with a number needed to treat of <4 patients (95% CI, 2–9 patients) to achieve a 50% improvement in the WOMAC score, which is a measure of joint pain, stiffness, and function.[35] Obesity and Infertility (Including Polycystic Ovary Syndrome) Obesity affects fertility throughout a woman's life. The impact of obesity and Polycystic Ovary Syndrome (PCOS) on reproductive function can be attributed to multiple endocrine mechanisms. Abdominal obesity is associated with an increase in circulating insulin levels. This results in increased functional androgen levels (caused by suppression of sex hormone–binding globulin synthesis and increased ovarian androgen production). Chronic elevation of circulating estrogen is caused by aromatization in peripheral adipose tissue. The resulting hyperandrogenism and menstrual cycle abnormalities are clinically manifested in part by anovulatory cycles and subfertility. Additionally, leptin inhibits ovarian follicular development and steroidogenesis and thus may contribute to reproduction difficulties in obese women. The impact of obesity on reproduction starts at a young age. Obese girls frequently experience the onset of puberty at a younger age than their normal-weight peers. Between the late 1960s and 1990, during a time of increasing prevalence of childhood obesity, the median age of menarche decreased by approximately 3 months in white girls and 5.5 months in black girls in the United States. Obesity negatively affects contraception. Older studies have shown that hormonal contraception methods are less effective in obese women.For example, a retrospective cohort analysis of 2822 person-years of oral contraceptive use suggested that women in the highest quartile of body weight (≥70.5 kg) had a 60% higher risk of failure than women of lower weight. This study also found that the increased risk of failure associated with weight was higher for women using very low-dose or low-dose oral contraceptives. However, a recent large cohort study in Europe did not show a difference in contraceptive efficacy of oral contraceptive pills based on BMI.[39] A multicenter study of 1672 healthy, ovulating, sexually active women randomized to receive the transdermal patch Ortho-Evra (Ortho-McNeil-Janssen Pharmaceuticals, Inc., Raritan, NJ) for 6 or 13 cycles found a higher rate of failure (pregnancy) in women weighing >90 kg (RR 58; 95% CI, 10.8–310. Additionally, a study of 1005 women using the levonorgestrol vaginal ring demonstrated higher rates of pregnancy at 1 year for heavier patients (1.7% for a 40-kg woman; 9.8% for an 80-kg woman).[37] Obesity is a risk factor for technical failure of tubal ligation surgery (OR, 1.7; 95% CI, 1.2–2.6).[40] The intrauterine device may be one of the few reliable contraception options whose efficacy does not seem to be affected by BMI.[37] Product inserts rarely comment on weight-specific guidelines (Table 4).

Although most attention has focused on the impact of obesity on ovulation, other studies suggest a multifactorial impact. A recent national survey in France found that obese women were less likely to access contraceptive health care services and had more unplanned pregnancies.[42] The US National Longitudinal Survey of Youth prospectively examined the association between body weight in young adulthood and achieved fertility in later life.[43] Obese young women and men were less likely to have their first child by the age of 47 than were their normal-weight counterparts (for women: RR, 0.69; 95% CI, 0.61–0.78; for men: RR, 0.75; 95% CI, 0.66–0.84). This association was partly explained by a lower probability of marriage among obese patients, suggesting both a social and biologic effect on reproductive behavior.[43]

A retrospective cohort study of 22,840 women demonstrated that obesity was associated with reduced fecundity for all weight-adjusted groups of women and persisted for women with regular cycles.[44] In addition, obesity may alter the quality of oocytes and embryos.[45] Some studies demonstrate increased female sexual dysfunction in obese patients, whether caused by the physical or psychological impacts of obesity on female sexuality.[36]

Obesity is frequently associated with disturbances in the menstrual cycle. Cross-sectional studies indicate that 30% to 47% of overweight and obese women have irregular menses.[46] PCOS frequently causes menstrual irregularity and is very common among obese women, though the actual prevalence is unclear. Although obesity may amplify the effects of PCOS, it is not a diagnostic criteria for PCOS. Approximately 20% of women with PCOS are not obese.[47]

Weight loss can improve the fertility of obese women by the return of spontaneous ovulation, thus leading to the recommendation of implementing weight-loss interventions (diet, exercise, medication treatment) as initial management of infertile overweight and obese women.[48]

A systematic review[49] assessing pregnancy and fertility after bariatric surgery reported that although the available data are not optimal, surgery may have a beneficial influence on fertility. This is supported by the normalization of hormones in PCOS and the correction of abnormal menstrual cycles after surgery.
Obesity and Pregnancy

An Australian study of more than 14,000 pregnant women found that 34% were overweight, obese, or morbidly obese.[50] In a US study of 9 states that included more than 66,000 women, there was a 22% rate of obesity among pregnant women in 2002 to 2003, which was up 69% since 1993.[51] The subgroups of women with the highest increases in obesity rates were women aged 20 to 29 years, were African American, who had ≥3 children, and who were enrolled in the US Department of Agriculture's Women, Infants, and Children program.[51] Obesity causes pregnancy complications because of elevated risks of antepartum complications and mechanical difficulties with delivery.

Obesity during pregnancy is related to higher overall health care expenditures, measured by length of stay after delivery and use of other services. The majority of this difference is caused by higher cesarean section rates and higher rates of high-risk obstetric conditions such as diabetes and hypertension. The mean length of stay after delivery was directly correlated to BMI[52] (3.6-day stay for women with a normal BMI vs 4.4-day stay for women with a BMI >40.0).

Prepregnancy obesity contributes to the development of many pregnancy complications including pregnancy-induced hypertension, preeclampsia, gestational diabetes, c-section, and neonatal death (Table 5). Compounding this finding is the fact that performing a cesarean section is more difficult in obese women.

Rates of fetal anomalies are increased in obese mothers as well, including neural tube defects (OR, 1.87; 95% CI, 1.62–2.15), spina bifida (OR, 2.24; 95% CI, 1.86–2.69), cardiovascular anomalies (OR, 1.30; 95% CI, 1.12–1.51), and cleft lip and palate (OR, 1.20; 95% CI, 1.03–1.40).[61] However, maternal obesity was protective for gastroschesis (OR, 0.17; 95% CI, 0.10–0.30).[61]

Weight loss via bariatric surgery s to decrease many pregnancy complications. A retrospective cohort study that included 585 women who had undergone bariatric surgery found that women who had delivered children after surgery (as compared with women who delivered before surgery) had decreased rates of hypertension during pregnancy (OR, 0.39; 95% CI, 0.20–0.74) and preeclampsia (OR, 0.20; 95% CI, 0.09–0.44). Another study compared women who delivered before surgery to women who delivered after surgery and found decreased rates of diabetes (17.3% vs 11%; P = .009), hypertensive disorders (23.6% vs 11.2%; P < .001), and fetal macrosomia (7.6% vs 3.2%; P = .004).[63] Obesity and Breastfeeding Maternal obesity is associated with a decreased intention to breastfeed, decreased initiation of breastfeeding, and decreased duration of breastfeeding. Some of these effects may be cultural, having to do with one's body image, or physiologic caused by metabolic and hormonal effects of adipose tissue (ie, decreased milk supply). However, obesity may also be related to some confounders such as more pregnancy complications, which also have negative effects on breastfeeding rates. A large study in the United Kingdom asked approximately 11,000 women at 32 weeks' gestation about their level of concern regarding their shape and weight. After adjusting for multiple variables, those with "marked concern" for both were significantly less likely to intend to breastfeed.[65] Another smaller study done in the United States among 114 women found that obese women intended to breastfeed for a significantly shorter period of time than other women.[66] Several studies have demonstrated decreased breastfeeding initiation rates among obese women compared with normal-weight women.64,[67–70] One chart review of 1109 white mother-baby dyads found that the overweight and obese mothers were more likely to quit breastfeeding at the time of discharge from the hospital compared with mothers who were normal weight (12.2% vs 4.3%).[67] Obese women are at greater risk of a delay in milk production, which may be related to decreased rates of breastfeeding initiation. One study found that obese women had lower prolactin responses to suckling in the first week compared with normal-weight women.[71] There is also evidence that excess body fat may impair mammary gland development before conception and during pregnancy by hormonal and metabolic effects.[72] Maternal obesity is also associated with a shortened duration of breastfeeding.[64,69,70,73,74] A Danish study of nearly 38,000 women observed that the greater the prepregnant BMI, the earlier the termination of breastfeeding.[73] There is no data looking at future breastfeeding rates with subsequent pregnancies after weight loss. Obesity and Depression Population-based studies looking at the association between obesity and depression have yielded inconsistent results, with only some finding an association.[75–78] The difference between sexes is similarly inconsistent. Some studies found an association between obesity and higher rates of depression in women but not in men;[79,81] others reported inverse associations between obesity and depression in both women and men.[81] Most recently, data from the third National Health and Nutrition Examination Survey (1988–1994) showed that obesity was associated with past-month depression in women (OR, 1.82; 95% CI, 1.01–3.3) but not in men (OR, 1.73; 95% CI, 0.56–5.37).[82] This relationship was stronger when obesity was stratified by severity. One 5-year prospective study following a cohort of 2298 persons from Alameda County, CA, showed that the obese were at increased risk of depression (prevalence: OR, 2.16; 95% CI, 1.47–3.19; incidence: OR, 2.11; 95% CI, 1.29–3.47) but there was no effect of sex on this association.[77] Although many social, psychological, and cultural factors likely contribute to the development of depression in obese women, one explanation argues that the stigma toward obese individuals in American society leads to low self-esteem and ultimately depression. Thus, in communities where a higher weight is acceptable, less psychological impact is observed. Another theory argues that obesity is not stressful per se, but the pressure to fit a norm and continued dieting leads to depression.[83] Obesity and Cancer in Women General There is mounting evidence that obesity is a risk factor for developing gynecologic and breast cancers and that a higher BMI may also adversely impact survival. Obese women with cancer may have decreased survival because of later screening, comorbid illnesses, or poorer response to treatment. Obese women have increased surgical and possibly radiation complications. In addition, there is no current consensus regarding appropriate chemotherapy dosing for the obese patient.[84] The increased levels of endogenous estrogen contribute to higher risk of several types of cancer.[85,86] Endometrial Cancer Endometrial carcinoma is strongly related to obesity. In premenopausal women, anovulation or oligoovulation that is associated with PCOS results in an endometrium that is chronically exposed to unopposed estradiol. This causes proliferation and the potential for neoplastic changes. Additionally, in premenopausal and postmenopausal obese women, increased insulin and androgens decrease the production of sex hormone–binding globulin. This leads to more and unregulated bioavailable estrogens in postmenopausal women. In 2001 the International Agency for Research on Cancer found that there was convincing evidence based on large cohort and case-control studies that obesity is associated with a 2- to 3-fold risk in endometrial cancer.[84,87] Epidemiologic data has found a 2- to 5-fold increased risk of developing endometrial carcinoma in premenopausal and postmenopausal women, and obesity has been associated with at least 40% of the incidence of endometrial cancer.[86,88,89] Mortality from uterine cancer also seems to increase with BMI. A prospective study through the American Cancer Society following 495,477 women found that those with a BMI >40 had an endometrial cancer mortality increased RR of 6.25 (95% CI, 3.75–10.42.).[85,90]

Ovarian Cancer The data linking ovarian cancer and obesity has been mixed.[91–93] The rationale for an increased risk of ovarian cancer in obese women focuses on the hormonal impact of obesity. In 2001, the International Agency for Research on Cancer group found that the "evidence from the relatively few studies on body weight and ovarian cancer has been inconsistent and does not allow any conclusion to be drawn on a possible association."[87] If some subtypes of ovarian cancer are hormonally responsive, it seems logical to assume that unopposed estrogen could increase the risk of these cancers in obese women.[84]

Cervical Cancer Several studies have shown both increased incidence and mortality from cervical cancer among obese women. This relationship may be because of decreased screening compliance among obese women.[84] Obesity likely plays a more prominent role in the development of cervical adenocarcinoma than squamous cell carcinoma secondary to the role of additional estrogenic hormones.[94] Disparities in cervical cancer screening by body weight persist for women who are severely obese. Obese white women may put off cervical cancer screening because of embarrassment or discomfort. Physicians recommend Papanicolaou smears for obese women at the same rate as for normal weight women.[95,96]

Breast Cancer There is a well-established link between obesity and postmenopausal breast cancer.[97] It is hypothesized that this is because of an increase in the serum concentration of bioavailable estradiol.[98] In 1997, a meta-analysis analyzed 51 studies, including 52,705 women with breast cancer and 108,411 women without breast cancer, and found that the strength of the estrogenic risk attenuated by obesity is stronger than with hormone replacement therapy. In fact, hormone replacement therapy does not increase the risk of breast cancer in obese, postmenopausal women (RR, 1.02 for BMI >25 kg/m2), though it is a significant risk for breast cancer in normal-weight women (RR, 1.73).[99,100]

Several meta-analyses, systematic reviews, and large cohort studies have shown obesity worsens breast cancer mortality. Obese women also have greater disease morbidity, including a higher recurrence rate, increased contralateral breast cancer, wound complications after breast surgery, and lymphedema.[101] Poorer outcomes associated with breast cancer may be related to more aggressive disease at diagnosis, a higher likelihood of treatment failure, and a higher likelihood of delayed detection. Morbidly obese women are significantly less likely to report recent mammography. This is particularly true for white women.[102,103] Obesity may also promote more rapid growth of metastatic disease because of impaired cellular immunity. In addition, the hyperinsulinemia found in some obese women may promote mammary carcinogenesis by increasing the levels of insulin-like growth factor and leptin, which have a synergistic effect with estrogen on mammary epithelial cells by promoting angiogenesis.[101]

Weight Loss and Cancer Studies evaluating the long-term impact of weight loss on cancer risk among women have shown mixed results. In one large US study, cancer incidence and mortality data were compared between 6596 patients who had gastric bypass (between 1984 and 2002) and 9442 morbidly obese persons who had not had surgery. This study showed decreased overall cancer rates in women (P < .0004), with the strongest impact on endometrial cancer (P < .0001) and with less significant impacts on premenopausal and postmenopausal breast cancer (P < .54), cervical cancer (P < .78), and ovarian cancer (P < .19).104 A large Swedish study followed 13,123 obesity surgery patients and found no overall decrease in obesity-related cancers compared with the baseline incidence among obese individuals. No statistically significant trends were found for breast cancer (P < .60) or endometrial cancer (P < .83) over time. Therefore, efforts directed toward prevention of obesity might be more helpful than weight reduction in attempts to reduce the incidence of obesity-related cancer.

Conclusion

Obesity is becoming more prevalent and has wide-ranging effects on a variety of women's health issues. Clinicians should counsel all women about the broad negative effects of obesity and the importance of controlling weight to prevent negative outcomes

Breast Implants, Safety and Efficacy of Silicone

eMedicine Specialties > Plastic Surgery > Breast

Author: Garry S Brody, MD, MSc, FACS, Professor Emeritus, Department of Surgery, Division of Plastic Surgery, Keck School of Medicine, University of Southern California
Updated: May 1, 2009


Background

The number of women in the United States who have breast implants is unknown, but current estimates derived from national surveys range up to more than 6 million. This represents more than 5% of the adult female population. The American Society of Plastic Surgeons (ASPS) collects information annually on plastic surgery procedures performed by its members. In 2008, approximately 307,000 women received breast implants for cosmetic breast augmentation and 111,000 for reconstruction of congenital or postmastectomy deformities.1 These data do not include those procedures (mostly cosmetic) performed by non plastic surgeons such as otolaryngologists, general surgeons, gynecologists, and others.

Following adverse publicity in the early 1990s, interest in the procedure fell significantly, especially for gel-filled devices, but it seems to have recovered incrementally. According to the ASPS, in 2008, 53% of total breast implants were filled with saline; 47% were filled with silicone.1

Prior to 1963, various plastic foam materials were used; for breast augmentation, however, it became apparent that the air cells would collapse and, combined with tissue ingrowth, shrink and harden the device. These materials were wrapped in plastic film to minimize this effect to no avail. Amazingly, some of these implants were so well tolerated that they have stayed in place to this day.

The modern silicone breast implant has been available since 1963 and has gone through an evolution of change and improvement. Several types of devices, with many variations, shapes and styles within each class, are now available or under testing for US Food and Drug Administration (FDA) approval. Basic to all implants is a silicone rubber (elastomer) shell, which can be single or double, smooth or textured, barrier-coated, or covered with polyurethane foam. The foam-covered devices have not been available in the United States since 1990 but are still marketed in Europe.

The contents are either factory-filled with silicone gel of various consistencies or inflated at surgery with normal saline. One brand that was manufactured overseas was prefilled with saline at the factory. It was briefly marketed in the United States but was later withdrawn when the FDA denied approval.

The double-lumen devices consist of concentric balloons that contain silicone in one chamber and saline in the other. The only one still in use is the Becker, which has an outer layer of gel and an inner balloon that is valved to permit postoperative gradual inflation with saline. This is termed a "permanent tissue expander," since it permits gradual and temporary overinflation to create the pocket and then can be left in as a permanent implant after the size is adjusted appropriately. At this writing, the Becker devices are not generally available in the United States until current FDA mandated studies are evaluated.2 For more information on expandable implants, see eMedicine article Uses of the Postoperatively Adjustable Implant in Aesthetic Breast Surgery.

In 1990, the FDA placed a moratorium on gel-filled implant use for cosmetic augmentation. They remained available for reconstruction and replacement, but mandated extensive record keeping, follow-up, and IRB approval were required for use. In 2006, after extensive study and analysis, the FDA deemed the device safe for all augmentation and reconstructive purposes, but they continue to require tracking of patients.

Saline Implants
Saline filled implants are available as empty silicone balloonlike devices to be filled with normal saline at the time of surgery. This permits subtle size adjustments to compensate for asymmetry between the breasts. They are less popular than silicone implants, as they often may have a less natural feel. If the patient has very little breast tissue or only a skin covering after mastectomy, unsightly wrinkles and folds of the device may be visible on the breast. This is more common when the surface is textured.

Silicone Gel Implants

Three generations of basic design of this device have been created, with many variations within each type.

First generation

The first models to be marketed had envelopes of thick, smooth-walled silicone elastomer made in 2 sections, filled with a viscous silicone gel material (dimethylsiloxane) and glued together. They were available in only three sizes: small, medium, and large. In the first few years, surgeons believed that the device required attachment to the tissues to prevent migration. Scar ingrowth for fixation was accomplished by patches of material (eg, Dacron mesh or perforated silicone) attached to the back of the device or by an outer covering of polyurethane foam. The Dacron and silicone patches were subsequently found to be unnecessary; they actually detracted from the quality of the result. Some patches or tabs created a stress point that led to tears of the envelope. Fixation patches were eliminated in the early 1970s.

Second generation

Manufacturers varied the gel consistency and shell thickness in an attempt to improve performance. Beginning in the mid-1970s, the shells were made thinner and the gel less viscous (ie, more "responsive"), primarily in an ill-conceived attempt to control hardening from scar shrinkage (capsular contracture.) This trend reversed in the early 1980s when it was recognized as not effective in reducing contracture and as resulting in a more fragile device. Most were broken 10 years later.

Third generation

New formulations of the shell and gel contents became available that were stronger and had a second barrier coat of diphenyl silicone. This coating almost totally eliminated so-called "gel bleed" or diffusion of small amounts of the silicone oil through the implant shell. The gel content also was made more viscous and cohesive.

In 1989, textured-surface shells that many surgeons hoped would minimize the incidence of unwanted firmness from capsular contracture became available. Recent studies are somewhat confusing regarding whether this was effective. The textured implants had the disadvantage of a higher rupture rate than the more traditional smooth shells and often produced visible wrinkles in the breast in women with very little overlying tissue to mask the ripples. Because of these shortcomings and lack of solid evidence that these devices were softer, they have become much less popular in recent years.

Polyurethane-covered implants

In the late 1960s, a variation of the device was developed containing a polyurethane sponge coating over an otherwise standard gel-filled implant. Although the coating originally was planned as a fixation layer, many surgeons came to believe that the foam cover resulted in a decreased incidence (or at least a delayed onset) of capsular contracture. These implants also evolved in shape and design, culminating in the early 1980s with the Meme and Optimam styles. In April 1991, the manufacturer voluntarily withdrew the foam-covered implants from the market.3

One style, the MemeME, had a unique construction. It had no true shell, but a skin of sorts was formed in situ by spraying the surface with silicone containing extra catalyst prior to curing. This increased the crosslinking of the surface to create a shell-like membrane. The polyurethane foam was then shaped and sealed over the surface. Implants of this particular type were known to occasionally extrude some of their gel contents through the foam when squeezed. This is a possible explanation for reports of blood being found within the substance of the gel in apparently intact implants. The MemeME model was marketed from 1983-1988.
Other filler materials

While silicone remains the only available shell material, new filler substances were in use in Europe and South America and, at one time, were under development or in experimental trial in the United States. Various hydrogels and a pure form of triglycerides were the 2 main formulations. The major advantage of the triglyceride formulation (Trilucent) was that it had a Z number (measure of radiolucency) similar to that of fat, thus resulting in little or no compromise of mammography. Another fill substance, polyvinyl pyrrolidone in saline, was briefly available, under the trade name Misty Gold. None of these products is currently available in the United States. At this time, only silicone gel or saline-filled models are available for use in the United States.

Recent developments

In late 2006, a new formulation of silicone gel filler called MemoryGel (Mentor Corp, Santa Barbara, Calif) gained FDA approval.4 This gel implant is thicker and more cohesive so as to minimize gel spread in the case of rupture and to resist scar shrinkage that would deform its contour. When cut, the gel retains its shape and doesn’t run. This device has a doughy feel to it.

Currently available devices in the United States are saline- or silicone-filled implants with either textured or smooth surfaces. They come in round or tear drop shapes with a choice of 3 different projections. Only 2 companies, Mentor Corporation and Allergen (a successor to McGhan and Inamed), have FDA approval to market these devices in the United States.

The implants produced currently are much improved devices compared to earlier units. The shell is still made of an outer layer of a mix of dimethyl siloxane and amorphous silica with an inner barrier coat of diphenyl siloxane to minimize silicone gel bleed. The shells, on testing for breakage, exceed the American Society for Testing and Materials (ASTM) requirements by more than 300%. The gel is more cohesive, varying from a standard 60% crosslinking to 80% for the more cohesive type nicknamed "gummy bear" (because of is consistency similar to the candy).

As evidenced by sales figures prior to the moratorium, and now following their release for cosmetic purposes, approximately 80-85% of surgeons and patients prefer the quality of results obtained by gel implants, making them the implants of choice. In 1997, sales figures for Europe, where usage was unrestricted, show a distribution of 70% for gel, 15% for saline, and 15% for alternate fills such as triglycerides (then still available) and hydrogels for cosmetic use.

Safety
Silicone is probably the most studied implantable material available today. After over 35 well-conducted studies from many countries, it seems certain that this material does not cause disease.
The results of more than 7 long-term follow-up studies show that women with implants have a reduced incidence of breast cancer than is otherwise expected in the general population.
No hard evidence reveals that a broken implant is harmful.
Almost all of the problems that can occur with breast implants, such as infection, hardening, extrusion, and malposition are related to the surgical procedure or the patient's own biology, not the device.

Summary

A great deal of recent safety research combined with more than 40 years of clinical experience has proven the value and relative safety of breast implants. Aside from the unique adverse effect of capsular contracture, the complication rate of this surgery approaches that of any clean elective procedure.
To date, no convincing evidence exists of any systemic disorder that can be attributed to silicone. As these are manmade devices, they have a failure rate and, in some patients, can require a significant amount of surgical maintenance. As with all natural body parts, these artificial substitutes may be subject to injury or disease and, when viewed from that perspective, have favorable risk-benefit characteristics

New Obesity Index Proposed, But Further Work Needed

From Heartwire

Lisa Nainggolan

March 3, 2011 (Los Angeles, California) — US researchers have developed a new index of adiposity that they say is a more accurate measure of body fat than the traditionally used body-mass index (BMI); the latter is calculated by dividing weight by height [1].

Using measurements of hip circumference and height, the new body adiposity index (BAI) can be used to reflect percentage of body fat for adult men and women of differing ethnicities, without numerical correction or assessment of weight, say Dr Richard N Bergman (University of Southern California, Los Angeles) and colleagues in their paper published online March 3, 2011 in Obesity.

It remains to be seen if the BAI is a more useful predictor of health outcome than other indexes of body adiposity, including the BMI.

However, they note that further work will be needed to extend and confirm their findings--tested in Mexican Americans and African Americans--to whites and other ethnic groups and to assess the role of the new index in children. And "it remains to be seen if the BAI is a more useful predictor of health outcome, in both males and females, than other indexes of body adiposity, including the BMI itself."

Height and Hip Size Most Strongly Relate to Percentage Adiposity

"We were interested in determining whether we could find an index of body adiposity that at least in some ways may be better than the BMI, which has been around since the 1840s" and is not a very accurate measure of adiposity in individual patients, Bergman explained to heartwire .
BMI is particularly inaccurate in people with elevated lean body mass, such as athletes, and in children, and it cannot be generalized among different ethnic groups, he and his colleagues note.

Bergman et al are not the first to propose an alternative to BMI. Waist circumference is widely thought to be a better indicator of cardiovascular risk than BMI, although some studies have shown them to be equally predictive.
Other examples include the waist-to-hip ratio (WHR) and the waist-to-hip-to-height index, which have both been forwarded as potentially better measures of obesity than BMI. But critics have said that it is difficult and time-consuming to get very accurate measurements of waist and hip circumference and height and that BMI has remained popular because it is simple and fast.

We looked at which variables most strongly related to percent adiposity, and they were height and hip size.

In their study, Bergman and colleagues used a large database, BetaGene, which consisted of relatives of Mexican Americans with gestational diabetes, to determine whether there might be a better index. They chose the Mexican American population because of its prevalence in Los Angeles, observing, "Most of the world population is nonwhite."

"We looked at which variables most strongly related to percent adiposity, and they were height and hip size. Because these variables were uncorrelated, we proposed a new index, the BAI, based upon these measures alone," Bergman explains.

BAI Will Be Easy to Calculate

"We showed that the BAI, calculated as (hip circumference/height1.5)–18, was a good predictor of percent fat and worked for men and women," he continues. The BAI also yielded the percentage of fat itself, rather than just a correlate (or index) of it, which is what the BMI does, he notes. The BAI was validated against the "gold standard" of dual-energy X-ray absorption (DEXA).

"It will be very easy for a physician or a nurse practitioner to work out this index for individual patients, using a calculator, a computer program, or an iPhone app," Bergman says.

The researchers then went on to corroborate their findings in another population, the Triglyceride and Cardiovascular Risk in African Americans (TARA) study, and found that the behavior of the BAI was quite similar between the blacks in that population and the Hispanics in BetaGene.

"Thus, we believe that we have presented evidence of accuracy at least in two ethnic populations, and further work on the generalizability of BAI to other groups is under way," they state. It will also be important to see whether the index can reliably forecast percentage of adiposity in children and predict risk of cardiovascular disease, they note.