Friday, January 27, 2012

Education for Mental Fitness: “A Sharper Mind, Middle Age and Beyond”

Kudos to Patri­cia Cohen for one of the best arti­cles I have read in The New York Times in a long time: A Sharper Mind, Mid­dle Age and Beyond, by Patri­cia Cohen. These are a few quotes — please do read the arti­cle in full, it is worth it.
  • Some peo­ple are much bet­ter than their peers at delay­ing age-related declines in mem­ory and cal­cu­lat­ing speed. What researchers want to know is why. Why does your 70-year-old neigh­bor score half her age on a mem­ory test, while you, at 40, have the mem­ory of a senior cit­i­zen? If inves­ti­ga­tors could bet­ter detect what pro­tects one person’s men­tal strengths or chips away at another’s, then per­haps they could devise a pro­gram to halt or reverse decline and even shore up improvements.”
  • As it turns out, one essen­tial ele­ment of men­tal fit­ness has already been iden­ti­fied. “Edu­ca­tion seems to be an elixir that can bring us a healthy body and mind through­out adult­hood and even a longer life,” says Margie E. Lach­man, a psy­chol­o­gist at Bran­deis Uni­ver­sity who spe­cial­izes in aging. For those in midlife and beyond, a col­lege degree appears to slow the brain’s aging process by up to a decade, adding a new twist to the cost-benefit analy­sis of higher edu­ca­tion — for young stu­dents as well as those think­ing about return­ing to school.”
  • Many researchers believe that human intel­li­gence or brain­power con­sists of dozens of assorted cog­ni­tive skills, which they com­monly divide into two cat­e­gories. One bunch falls under the head­ing “fluid intel­li­gence,” the abil­i­ties that pro­duce solu­tions not based on expe­ri­ence, like pat­tern recog­ni­tion, work­ing mem­ory and abstract think­ing, the kind of intel­li­gence tested on I.Q. exam­i­na­tions. These abil­i­ties tend to peak in one’s 20s.”
  • Crys­tal­lized intel­li­gence,” by con­trast, gen­er­ally refers to skills that are acquired through expe­ri­ence and edu­ca­tion, like ver­bal abil­ity, induc­tive rea­son­ing and judg­ment. While fluid intel­li­gence is often con­sid­ered largely a prod­uct of genet­ics, crys­tal­lized intel­li­gence is much more depen­dent on a bou­quet of influ­ences, includ­ing per­son­al­ity, moti­va­tion, oppor­tu­nity and culture.
  • At a time when the prospect of a longer life is shad­owed by the fear of men­tal decline, the pos­si­bil­ity that the aging can have some con­trol over their men­tal fit­ness is an idea even William Osler would support.”
Full arti­cle: A Sharper Mind, Mid­dle Age and Beyond, by Patri­cia Cohen.

Build Your Cognitive Reserve

 sharpbrains » JUL 23, 2007

Build Your Cognitive Reserve-Yaakov Stern
By: Alvaro Fernandez

Dr. Yaakov Stern is the Divi­sion Leader of the Cog­ni­tive Neu­ro­science Divi­sion of the Sergievsky Cen­ter, and Pro­fes­sor of Clin­i­cal Neu­ropsy­chol­ogy, at the Col­lege of Physi­cians and Sur­geons of Colum­bia Uni­ver­sity, New York.
 He is one of the lead­ing pro­po­nents of the Cog­ni­tive reserve the­ory, which aims to explain why some indi­vid­u­als with full Alzheimer’s pathol­ogy (accu­mu­la­tion of plaques and tan­gles in their brains) can keep nor­mal lives until they die, while oth­ers –with the same amount of plaques and tan­gles– dis­play the severe symp­toms we asso­ciate with Alzheimer’s Dis­ease.
He has pub­lished dozens of peer-reviewed sci­en­tific papers on the subject.

 The con­cept of a Cog­ni­tive Reserve has been around since 1989, when a post mortem analy­sis of 137 peo­ple with Alzheimer’s Dis­ease showed that some patients exhib­ited fewer clin­i­cal symp­toms than their actual pathol­ogy sug­tested.
These patients also showed higher brain weights and greater num­ber of neu­rons when com­pared to age-matched con­trolls.
The inves­ti­ga­tors hypoth­e­sized that the patients had a larger “reserve” of neu­rons and abil­i­ties that enable them to off­set the losses caused by Alzheimer’s.
Since then, the con­cept of Cog­ni­tive Reserve has been defined as the abil­ity of an indi­vid­ual to tol­er­ate pro­gres­sive brain pathol­ogy with­out demon­strat­ing clin­i­cal cog­ni­tive symp­toms.

 Key take-aways -
Life­time expe­ri­ences, like edu­ca­tion, engag­ing occu­pa­tion, and leisure activ­i­ties, have been shown to have a major influ­ence on how we age, specif­i­cally on whether we will develop Alzheimer’s symp­toms or not.
This is so because stim­u­lat­ing activ­i­ties, ide­ally com­bin­ing phys­i­cal exer­cise, learn­ing and social inter­ac­tion, help us build a Cog­ni­tive Reserve to pro­tect us.
The ear­lier we start build­ing our Reserve, the bet­ter; but it is never too late to start.
And, the more activ­i­ties, the bet­ter: the effect is cumulative.

The Cog­ni­tive Reserve
 Alvaro Fer­nan­dez (AF): Dear Dr. Stern, it is a plea­sure to have you here. Let me first ask you this: the impli­ca­tions of your research are pretty astound­ing, pre­sent­ing major impli­ca­tions across sec­tors and age groups. What has been the most unex­pected reac­tion so far?

 YS: well…I was pretty sur­prised when, years ago, a reporter from Sev­en­teen mag­a­zine requested an inter­view. I was really curi­ous to learn why she felt that her read­ers would be inter­ested in stud­ies about demen­tia. What she told me showed a deep under­stand­ing and insight: she wanted to moti­vate chil­dren to stay in school. She under­stood that early social inter­ven­tions could be very pow­er­ful for build­ing reserve and pre­vent­ing dementia.

 AF: That’s great…so let’s now fast for­ward, say, 60 years from our high-school years, and sup­pose that per­sons A and B both tech­ni­cally have Alzheimer’s (plaques and tan­gles appear in the brain), but only A is show­ing the dis­ease symp­toms. What may explain this discrepancy?

 YS: Indi­vid­u­als who lead men­tally stim­u­lat­ing lives, through edu­ca­tion, occu­pa­tion and leisure activ­i­ties, have reduced risk of devel­op­ing Alzheimer’s. Stud­ies sug­gest that they have 35–40% less risk of man­i­fest­ing the dis­ease. The pathol­ogy will still occur, but they are able to cope with it bet­ter. Some won’t ever be diag­nosed with Alzheimer’s because they don’t present any symp­toms. In stud­ies that fol­low healthy elders over time and then get autop­sies, up to 20% of peo­ple who did not present any sig­nif­i­cant prob­lem in the daily lives have full blown Alzheimer’s pathol­ogy in their brains.

 AF: What exactly may be going on in the brain that pro­vides that level of protection?

 YS: There are two ideas that are com­ple­men­tary. One idea (called Brain Reserve by researchers) pos­tu­lates that some indi­vid­u­als have a greater num­ber of neu­rons and synapses, and that some­how those extra struc­tures pro­vide a level of pro­tec­tion. In a sense, we have more “hard­ware”, pro­vid­ing a pas­sive pro­tec­tion against the attacks of Alzheimer’s.
The other the­ory (called Cog­ni­tive Reserve) empha­sizes the build­ing of new capa­bil­i­ties, how peo­ple can per­form tasks bet­ter through prac­tice, and how these skills become so well learned that they are not too easy to unlearn. Like devel­op­ing new and refined “software”.

 AF: But, both seem to go hand in hand, cor­rect? Neu­ro­plas­tic­ity means that what you call “hard­ware” and “soft­ware” are two sides of the same coin and they influ­ence each other, right?

 YS: Cor­rect. So these days we don’t make a sharp dis­tinc­tion, and are con­duct­ing more neu­roimag­ing stud­ies to bet­ter under­stand the rela­tion­ship between both.

 Build­ing Your Cog­ni­tive Reserve

 AF: OK, so our goal is to build that Reserve of neu­rons, synapses, and skills. How can we do that? What defines “men­tally stim­u­lat­ing activ­i­ties” or good “brain exercise”?

 YS: In sum­mary, we could say that “stim­u­la­tion” con­sists of engag­ing in activ­i­ties. In our research almost all activ­i­ties are seen to con­tribute to reserve. Some have chal­leng­ing lev­els of cog­ni­tive com­plex­ity, and some have inter­per­sonal or phys­i­cal demands.
In ani­mal stud­ies, expo­sure to an enriched envi­ron­ment or increased phys­i­cal activ­ity result in increased neu­ro­ge­n­e­sis (the cre­ation of new neu­rons).
You can get that stim­u­la­tion through edu­ca­tion and/ or your occu­pa­tion. There is clear research show­ing how those two ele­ments reduce the risk.
Now, what is very excit­ing is that, no mat­ter one’s age, edu­ca­tion and occu­pa­tion, our level of par­tic­i­pa­tion in leisure activ­i­ties has a sig­nif­i­cant and cumu­la­tive effect.
A key mes­sage here is that dif­fer­ent activ­i­ties have inde­pen­dent, syn­er­gis­tic, con­tri­bu­tions, which means the more things you do and the ear­lier you start, the bet­ter.
But you are never stuck: bet­ter late than never.

 AF: Can you give us some exam­ples of those leisure activ­i­ties that seem to have the most pos­i­tive effects?
 YS: For our 2001 study we eval­u­ated the effect of 13 activ­i­ties, com­bin­ing intel­lec­tual, phys­i­cal, and social ele­menus.
Some of the activ­i­ties with the most effect were read­ing, vis­it­ing friends or rel­a­tives, going to movies or restau­rants, and walk­ing for plea­sure or going on an excur­sion.
As you can see, a vari­ety. We saw that the group with high level of leisure activ­i­ties pre­sented 38% less risk (con­trol­ling for other fac­tors) of devel­op­ing Alzheimer’s symp­toms.
And that, for each addi­tional type of activ­ity, the risk got reduced by 8%.
There is an addi­tional ele­ment that we are start­ing to see more clearly.
Phys­i­cal exer­cise, by itself, also has a very ben­e­fi­cial impact on cog­ni­tion. Only a few months ago researchers were able to show for the first time how phys­i­cal activ­ity pro­motes neu­ro­ge­n­e­sis in the human brain. So, we need both men­tal and phys­i­cal exer­cise.
The not-so-good news is that, as of today, there no clear recipe for suc­cess. More research is needed before we pre­pare a sys­tem­atic set of inter­ven­tions that can help max­i­mize our protection.

 AF: We typ­i­cally empha­size the impor­tance of a good nutri­tion, phys­i­cal exer­cise, stress man­age­ment and men­tal exer­cise that presents nov­elty, vari­ety and chal­lenge. What do you think of the rel­a­tively recent appear­ance of so many computer-based cog­ni­tive train­ing pro­grams, some more science-based than others?

 YS: Those ele­ments you men­tion make sense. The prob­lem is that, at least from the point of view of Alzheimer’s, we can­not be much more spe­cific. We don’t know if learn­ing a new lan­guage is more ben­e­fi­cial than learn­ing a new musi­cal instru­ment or using a computer-based pro­gram. A few of the cog­ni­tive train­ing com­puter pro­grams we have seen, like the one you dis­cussed with Prof. Daniel Gopher to train the men­tal abil­i­ties of pilots, seem to have clear effects on cog­ni­tion, gen­er­al­iz­ing beyond the train­ing itself. But, for the most part, it is too early to tell the long-term effects. We need bet­ter designed clin­i­cal tri­als with clear con­trols. Right now, the most we can say is that those who lead men­tally stim­u­lat­ing lives, through edu­ca­tion, occu­pa­tion and leisure activ­i­ties seem to have the least risk of devel­op­ing Alzheimer’s Disease.

 Research inter­ests
 AF: Tell us know a bit more about your cur­rent research
 YS: We are study­ing a num­ber of related areas, apply­ing neu­roimag­ing tech­niques to under­stand how exactly all these Cog­ni­tive Reserve con­cepts are imple­mented in the brain. One, we want to under­stand indi­vid­ual dif­fer­ences in how peo­ple approach tasks. We want to mea­sure their effi­ciency and capac­ity the brain net­works that medi­ate tasks per­for­mance with the idea that those with greater effi­ciency and capac­ity might cope bet­ter with age-related prob­lems.
For exam­ple, we can all under­stand that a com­pet­i­tive swim­mer is going to swim bet­ter than I would even if he has some weights in his legs, but we haven’t yet iden­ti­fied what exactly is the equiv­a­lent in the brain. Sec­ond, we want to under­stand how old peo­ple com­pen­sate for the areas of decline.
For exam­ple, do they begin to use new brain areas when the ones that are typ­i­cally used start to fail. Third, whether the Cog­ni­tive Reserve presents ben­e­fits beyond the pre­ven­tion of Alzheimer’s symp­toms. Does hav­ing a higher reserve result in bet­ter atten­tion, bet­ter exec­u­tive func­tions, more suc­cess­ful aging overall?

 AF: All very impor­tant top­ics. And I am sure every­one read­ing this inter­view will devour any new details on how to build our Cog­ni­tive Reserves. Thank you for your time, and please keep us informed.

 YS: My plea­sure. Thank you for your great edu­ca­tional initiative. ————————————

Tuesday, January 24, 2012

Sexual Activity n Heart cases

From Heartwire
 Lisa Nainggolan
 January 19, 2012 (Houston, Texas)

 New advice indicates that sexual activity is safe for the majority of heart disease patients and that doctors--as well as patients and their partners--should endeavor to bring up the subject of sex in discussions.
The guidance comes from the first-ever American Heart Association (AHA) scientific statement to address the issue, which is published online today in Circulation.
 Lead author Dr Glenn N Levine (Baylor College of Medicine, Houston, TX) told heartwire that the recommendations are probably the most comprehensive on the subject to date and have been compiled by experts from various fields, including cardiology, exercise physiology, sexual counseling, and urology. Physicians, patients, and partners are reluctant to talk about sexual activity, but it is something "that is important to quality of life for most people, and we would not want to see patients refraining from sex out of undue concern about precipitating a heart attack or sudden death," he observes.

 We would not want to see patients refraining from sex out of undue concern about precipitating a heart attack or sudden death.
 The only patients who should refrain from sex are those with unstable heart disease or severe symptoms; they should be assessed and stabilized with appropriate treatment before engaging in sexual activity, says Levine. And drugs that can improve cardiovascular symptoms or survival should not be withheld due to concerns that they may have an impact on sexual function, he notes.

 He also stresses that while use of phosphodiesterase-5 (PDE-5) inhibitor erectile-dysfunction drugs, such as sildenafil (Viagra, Pfizer) are generally safe for men who have stable cardiovascular disease, these agents are absolutely contraindicated in patients receiving nitrate therapy, either long-acting preparations or sublingual ones. Fear, Anxiety, and Depression Can Underlie Avoidance of Sex

 The AHA guidance gives general recommendations for sexual activity and CVD but also advice pertaining to patients with specific conditions: coronary artery disease; heart failure; valvular heart disease; those with arrhythmias and/or pacemakers or implantable cardioverter defibrillators (ICDs); congenital heart disease; and hypertrophic cardiomyopathy. And it covers cardiovascular drugs and sexual function as well as pharmacotherapy for sexual dysfunction.

 One of the main purposes of the statement "is to make physicians and healthcare providers aware that this is a real issue that is not appropriately addressed with the patient and partner and truly should be," says Levine. "

At the same time--because we are getting a lot of lay press attention to this issue--we hope to make patients and their partners aware that sexual activity is something they should feel free to discuss with their healthcare providers during an office visit or before hospital discharge.
 We hope to make patients and their partners aware that sexual activity is something they should feel free to discuss with their healthcare providers.
 "The important thing to emphasize is that the risk of heart attack with sexual activity is only extremely modestly increased during sexual activity and represents only a miniscule amount of a person's overall risk."
 Levine also wants to highlight the fact that anxiety and depression should be important considerations in patients with cardiovascular disease and can contribute to reduced or impaired sexual activity.
"Sexual counseling of CVD patients and their partners is an important component of recovery; unfortunately, it is rarely provided," he and his coauthors observe.
 Advice Should Help All Doctors to Advise CVD Patients on Sex The scientific statement has been published in a cardiology journal, Levine notes, because "the cardiologist is going to be asked to comment on this, and frequently the GP will often refer the patient to the cardiologist to address issues" relating to sexual activity, he notes.
For example, one subject he is frequently consulted about by other doctors is whether patients can use erectile-dysfunction drugs. Levine hopes, however, that the new recommendations will embolden other specialists to confidently advise patients: "One of the aims is to allow GPs, family doctors, and others to, at least for the majority of patients, give reasonable guidance." Another important consideration raised in the AHA statement--which is also endorsed by the American Urological Association, Society for Cardiovascular Angiography and Interventions, Society of Thoracic Surgeons, American Association of Cardiovascular and Pulmonary Rehabilitation, International Society of Sexual Medicine, American College of Cardiology Foundation, Heart Rhythm Society, and Heart Failure Society of America--is that cardiac rehabilitation and regular physical activity can reduce the risk of cardiovascular complications in people with heart disease.
 Exercise testing can also provide additional information as to the safety of sexual activity in patients with indeterminate or unclear risk, the authors note.

 They conclude that further research is needed on sexual activity in specific cardiovascular conditions, particularly with regard to the effects in females and in older adults.
 Levine has reported that he has no conflicts of interest. Disclosures for the coauthors are listed in the paper.

Even Mild Dehydration May Cause Emotional, Physical Problems

From WebMD Health News Denise Mann January 20, 2012 Even mild dehydration may affect our moods and ability to concentrate. In a new study of 25 healthy women, mild dehydration dampened moods, increased fatigue, and led to headaches. The women in the study were aged 23, on average. They were neither athletes nor couch potatoes. Women participated in three experiments separated by 28 days. In two of these, dehydration was induced via walking on a treadmill with or without a diuretic pill. These pills encourage urination, and can lead to dehydration. The women were given a battery of tests measuring their concentration, memory, and mood when they were dehydrated and when they were not. Overall, women’s mental ability was not affected by mild dehydration. But they did have an increase in perception of task difficulty and lower concentration. But “women were more fatigued and this was true during mild exercise and when sitting at a computer,” says researcher Lawrence E. Armstrong, PhD. He is a professor of environmental and exercise physiology at the University of Connecticut's Human Performance Laboratory in Storrs, Conn. The findings appear in The Journal of Nutrition. Armstrong and colleagues previously looked at the effects of mild dehydration in men. Although men did experience some subtle mental difficulties when dehydrated, the risks were pretty similar between the sexes. The message is clear, he says: “We should focus on hydration and continue to drink during meals and when we are not at meals.” Avoid Dehydration: Drink More Water You are often already dehydrated once you become thirsty, but subtle cues like a headache and/or fatigue can be your body’s way of telling you to drink more water, Armstrong says. The new study should serve as a reminder for healthy, young women who frequently exercise to drink water, says Robert Glatter, MD. He is an emergency medicine physician at Lenox Hill Hospital in New York City. “Consume moderate quantities of water both during and after exercise in order to avoid mild dehydration, which may lead to headaches, fatigue, and difficulty concentrating,” he says in an email. “Just a small change in state of hydration was enough to affect mood, ability to concentrate, and lead to development of headaches.” It is unclear if these findings apply to other populations at risk for dehydration, such as the elderly, people with diabetes, and children, Glatter says. The best way to avoid becoming dehydrated is to drink an adequate amount of water. Olveen Carrasquillo, MD, agrees. He is the chief of the division of general internal medicine at University of Miami Miller School of Medicine. So, how much water do we need? “For most healthy people, six to eight glasses of 8 ounces of water a day is what we recommend,” he says. The effects of even mild dehydration are likely to be even more pronounced in high-risk groups, such as the elderly and young children. Knowing the signs of dehydration can also keep you out of the danger zone. Another sign is dark urine. “Your urine should be a light yellow color,” Glatter tells WebMD. Not everyone needs to drink this much water. “People with congestive heart failure and people with certain kinds of kidney disease may want to limit their fluid intake, and should talk to their doctor about how much water they should drink,” he says. SOURCES: Armstrong L.E. Journal of Nutrition, 2102.

Physical Activity Yields Better Academic Performance in Children

From Medscape Education Clinical Briefs News Author: Larry Hand CME Author: Penny Murata, MD 01/10/2012 Clinical Context The evidence for a relationship between physical activity and academic performance is not conclusive. A review by Trudeau and Shephard in the February 25, 2008, issue of the International Journal of Behavioral Nutrition and Physical Activity found a positive link between physical activity and academic performance, based on cross-sectional studies. A review by Taras in the August 2005 issue of the Journal of School Health reported possible acute benefits of physical activity on academic performance. This systematic review by Singh and colleagues assesses the longitudinal relationship between physical activity and academic performance in children. Study Synopsis and Perspective Concerned that physical activity times in schools might be cut back to make room for more academic study to improve test scores, researchers in the Netherlands conducted a systematic review of published studies and found that moderate to vigorous physical activity may actually improve academic performance in children and adolescents. In an article published in the January issue of the Archives of Pediatrics and Adolescent Medicine, researchers led by Amika Singh, PhD, from the Vrije Universiteit University Medical Center at EMGO Institute for Health and Care Research in Amsterdam, the Netherlands, write, "According to the best-evidence synthesis, we found strong evidence of a significant positive relationship between physical activity and academic performance." After searching 4 databases, the researchers screened 844 potentially related articles and determined that 14 qualified as relevant to their hypothesis. Of those 14 studies, 12 were performed in the United States, 1 was Canadian, and 1 was South African. Sample sizes ranged from 53 to 12,000 individuals aged 6 through 18 years, and follow-up duration ranged from 8 weeks to more than 5 years. The researchers rated only 2 of the 14 studies as having high methodologic quality. One of those studies was observational and the other was interventional. "[B]oth high-quality studies supported our hypothesis of physical activity being positively related to academic performance in children," they write. The studies they reviewed measured physical activity based on school athletic participation, self-reported physical activity questionnaires, or in the case of intervention studies, increased physical activity in schools during the study period. The studies measured academic achievement by self-reported grades, by cognitive test scores, or by both. The academic areas included reading, math, world studies, and history. The researchers concluded that although few published studies have assessed the link between physical activity and academic performance, enough evidence exists to report that "physical activity is positively related to academic performance in young people." They call for more high-quality studies to explore the mechanisms of such a relationship and to explore more physical activities than just school sports participation. The authors have disclosed no relevant financial relationships. Arch Pediatr Adolesc Med. 2012;166:49-55. Abstract

Wednesday, January 18, 2012

1 in 3 US Adults, 1 in 6 US Children Obese

From Medscape Medical News Laura Newman, MA January 17, 2012 — The US prevalence of obesity continues to be high, with one third of US adults and 1 in 6 US children and adolescents affected, according to 2009 to 2010 data from the National Health and Nutrition Examination Survey (NHANES). The data were presented in 2 papers published online January 17 in JAMA. As alarming as these rates are, the data suggest that they may be topping out, according to the researchers. "[Obesity prevalence] increased significantly over the 12-year period from 1999 through 2010 for men and for non-Hispanic black and Mexican American women, but did not change between 2003-2009 and 2010 for men or women," write Katherine M. Flegal, PhD, distinguished consultant from the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention, Hyattsville, Maryland, and colleagues in the first article. In addition, trends in US children and teenagers followed a similar pattern — unchanged, but at 17% — since the last review of 2007-2008, explain Cynthia L. Ogden, PhD, MRP, NCHS epidemiologist, and colleagues in the second article, on children and teenagers. Noting the linear increase in obesity prevalence in children, and predictions that obesity prevalence among children and teenagers may reach 30% by 2030, the authors write that "the data presented herein suggest that the rapid increases in obesity prevalence seen in the 1980s and 1990s have not continued in this decade and may be leveling off." Among US adults, the age-adjusted obesity prevalence was 35.7% (95% confidence interval [CI], 33.8% - 37.7%). Non-Hispanic black men and women had the highest obesity prevalence rates, at 38.8% (95% CI, 33.9% - 43.9%) for men and 58.5% (95% CI, 52.4% - 64.3%) for women. When age-adjusted prevalence of overweight and obesity were combined (body mass index [BMI] of at least 25 kg/m2), it was 68.8% overall (95% CI, 65.9% - 71.5%), 73.9% for men (95% CI, 70.0% - 77.8%), and 63.7% among women (95% CI, 60.9% - 66.4%. Grade 2 obesity, defined as a BMI of 35 kg/m2 or more, and grade 3 obesity (BMI, 40 kg/m2 or more) again show the highest rates for non-Hispanic blacks, at 20.0% (95% CI, 16.4% - 24.3%) for non-Hispanic black men and 30.7% (95% CI, 26.4% - 35.2%) for non-Hispanic black women. In the study of children and teenagers, investigators used high weight for recumbent length (BMI 95th percentile or higher of the BMI-for-age growth charts). Between 2009 and 2010, 16.9% of US children and adolescents were obese (95% CI, 15.4% - 18.4%), with 31.8% either overweight or obese (95% CI, 29.8% - 33.7%). Boys were consistently more likely to be obese than girls, at 18.6% vs 15.0%. =Racial differences were also striking, with black children and adolescents having an obesity of prevalence of 24.3% (95 CI, 20.5% - 28.6%) compared with 21.2% (95 CI, 19.5% - 23.0%) for Hispanics and 14.0% (95% CI, 11.7% - 16.7%) for non-Hispanic whites. Older children had higher prevalence rates than each successive younger age group. NHANES analyses are based on at-home interviews and physical examinations collected continuously since 1999 in children, and since 1960 in adults, and released in 2-year cycles. NHANES is designed as a cross-sectional survey nationally representative of the US noninstitutionalized population. Data from other industrialized countries also suggest that obesity trends may be leveling off worldwide. The authors have disclosed no relevant financial relationships. JAMA. Published online January 17, 2012. Flegal full text, Ogden full text