Triglyceride and Waist Measurements Predict Heart-Disease Risk

From Heartwire
Triglyceride and Waist Measurements Predict Heart-Disease Risk

Sue Hughes

July 19, 2010 (Quebec, Quebec City) — Using two simple and inexpensive measurements--triglycerides and waist circumference--can identify patients with intra-abdominal obesity who have an increased risk of coronary artery disease and can add value in detecting risk of heart disease when used with traditional risk models such as Framingham, a new study suggests.

The study, published online July 19, 2010 in the Canadian Medical Association Journal, was conducted by a team led by Dr Benoit Arsenault (l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, QC).

A Step Beyond Metabolic Syndrome?

Coauthor Dr Jean Pierre Després (l'Institut Universitaire de Cardiologie et de Pneumologie de Québec) told heartwire that he believes the combination of a large waist measurement plus high triglyceride level, termed the "hypertriglyceridemic-waist phenotype," is the next step beyond metabolic syndrome.

"We are not proposing that this is a new definition of metabolic syndrome. But we are suggesting that this is a new phenomenon beyond the metabolic syndrome that can identify individuals at increased risk of heart disease who may fall through the net if we just use traditional risk factors," he said.

This is a new phenomenon beyond the metabolic syndrome that can identify individuals at increased risk of heart disease who may fall through the net if we just use traditional risk factors.

Metabolic syndrome, a condition that is the subject of much argument over its relevance, is defined as having three of the following risk factors: increased waist circumference, elevated triglycerides, reduced HDL cholesterol, elevated blood pressure, or elevated fasting glucose.
The latter three risk factors are normally measured as part of traditional risk evaluations for heart disease, so Després is saying that the focus should therefore be on waist and triglycerides, which have now been shown to add value over and above traditional risk factors.

"These two simple measurements are the cheapest way of finding those people who are at risk from this lousy lifestyle we now lead--those with visceral obesity and related metabolic disorders. Because it is measuring the two components of the metabolic syndrome not captured by Framingham or other traditional risk scores, it is picking up the risk of metabolic syndrome not found by those traditional scores," he added.

In the paper, the authors explain that although obesity is a health hazard, not every obese person has the expected metabolic abnormalities associated with excess body fat, and these tend to occur more often in those people with an excess of intra-abdominal or visceral adipose tissue. They have previously proposed that waist circumference can be used as an easy measurement of intra-abdominal adiposity, with elevated triglyceride levels further identifying "dysfunctional" adipose tissue. They suggest that hypertriglyceridemia combined with an increased waistline could be a marker of lipid overflow resulting from a relative defect of adipose tissue to clear and store the excess triglycerides from overeating and lack of physical activity.

EPIC-Norfolk Study

In the current study, they report on the performance of this phenotype as a screening tool for coronary heart disease among participants in the EPIC-Norfolk study, a population-based study involving 25 668 men and women aged 45 to 79 years in Norfolk, UK, who completed a baseline questionnaire and attended a clinic visit.

These two simple measurements are the cheapest way of finding those people who are at risk from this lousy lifestyle we now lead.

The hypertriglyceridemic-waist phenotype was defined as a waist circumference of 90 cm or more and a triglyceride level of 2.0 mmol/L or more in men and a waist circumference of 85 cm or more and a triglyceride level of 1.5 mmol/L or more in women.

Coronary artery disease developed in 2109 participants during the study follow-up. Compared with participants who had a waist circumference and triglyceride level below the threshold, those with the hypertriglyceridemic-waist phenotype had higher blood pressure, higher levels of apolipoprotein B and C-reactive protein, lower levels of HDL cholesterol and apolipoprotein A-I, and smaller LDL particles.

Both men and women with the hypertriglyceridemic-waist phenotype had an increased risk of developing heart disease than those who did not have the phenotype, and this increase remained significant after researchers accounted for traditional risk factors.

Hazard Ratio for Heart Disease With Hypertriglyceridemic-Waist Phenotype
Group Unadjusted HR (95% CI) Adjusted* HR (95% CI)
Men 2.40 (2.02–2.87) 1.28 (1.07–1.54)
Women 3.84 (3.20–4.62) 1.67 (1.35–2.06)

*Adjusted for age, total cholesterol level, HDL, systolic blood pressure, smoking status, and presence of diabetes

Després believes the measurement of triglycerides and waist is particularly important to pick up patients who have normal traditional risk scores. "If they have hypertension or diabetes or raised cholesterol, they will be picked up with traditional methods, but we found in our study that patients with normal values on traditional risk scores had double or triple the risk of developing heart disease if they had hypertriglyceridemic waist. It is these people who are slipping through the net at the moment but can be easily identified with these two simple tests," he added.