DALLAS, April 19 – A tape measure and a simple blood test may be the best way to gauge cardiovascular risk for postmenopausal women, according to a report published today in an obesity-themed issue of Circulation: Journal of the American Heart Association.
Women who had an enlarged waist and elevated levels of blood fats known as triglycerides had almost a fivefold increased risk of fatal cardiovascular events compared to women without those traits.
Enlarged waist and elevated triglycerides (EWET) are two of five risk factors that the National Cholesterol Education Program (NCEP) uses to characterize the metabolic syndrome (MS). The others are elevated blood pressure, low HDL “good” cholesterol, and impaired fasting blood glucose. Having three of the five factors constitutes a metabolic syndrome diagnosis.
The investigation is the first long-term study in a community-based gender-specific population that suggests EWET is a stronger predictor of cardiovascular risk in postmenopausal women than the NCEP-defined metabolic syndrome.
“A woman who has an enlarged waist and elevated triglycerides is very likely to have a kind of apple shape, with predominant upper body fat accumulation and relatively under-developed lower body fat accumulation,” said Laszlo Tanko, M.D., Ph.D., a senior research physician at the Center for Clinical and Basic Research in Ballerup, Denmark. “This type of obesity is prone to an array of metabolic alterations that increases markedly the relative risk of adverse outcomes.”
EWET is defined as waist circumference of at least 88 centimeters (35.2 inches) and a triglyceride level of at least 1.45 millimoles per liter (or 128 milligrams per deciliter). Triglycerides reflect the body’s ability to respond to insulin. When the ability is insufficient, triglyceride levels increase, reflecting a characteristic accumulation of atherogenic fatty substances in the blood.
“We believe that obesity poses a cardiovascular risk in these women who, for some reasons, deposit extra pounds centrally in the intra-abdominal compartment, and do not follow the pattern of depositing primarily to the peripheral fat depots – hips, thighs, buttocks – as most women do,” he said.
Researchers evaluated 557 postmenopausal women ages 48-76 years. They followed the women for about 8.5 years to evaluate the value of an EWET criteria for predicting all-cause death and death from cardiovascular causes.
At the start of the study, 15.8 percent of the women had EWET and 17.6 percent met the diagnostic criteria for metabolic syndrome. About two-thirds of those with metabolic syndrome also met criteria for EWET. Ninety-five deaths occurred during follow-up.
All-cause and cardiovascular deaths were significantly increased in women with either EWET or metabolic syndrome. However, the presence of EWET was associated with a 4.7-fold increased risk of cardiovascular death compared to women without EWET. Women who had metabolic syndrome had a 3.2-fold increased risk compared to women without the condition.
Half of the cardiovascular deaths occurred in women with EWET, compared to 44.6 percent in women with metabolic syndrome; so EWET could be a simple and inexpensive screening tool to identify postmenopausal women who are at increased risk of premature cardiovascular death.
“Because two-thirds of women who die suddenly of cardiovascular disease have no previous recognized symptoms, it is essential to find effective indicators of cardiovascular risk that could facilitate timely referral for those who would benefit from adequate prevention,” Tanko said.
“For women who have a waistline exceeding 88 cm and triglycerides exceeding 1.45 mmol/L at the same time, diet- and exercise-induced weight loss is highly recommended to reduce the almost five-fold increased risk for dying of cardiovascular disease compared with those who do not possess these risk factors or indicators,” he said. “Although it sounds simple and repetitive, we believe this is the most effective way of eliminating the source of the problem. Luckily, upper-body fat mass responds relatively rapidly to diet and exercise changes. The challenge is to maintain these achieved benefits and obtain lasting prevention.”
The findings add to previous work by Danish researchers indicating that body weight or body mass index by itself may not be as important in assessing atherosclerotic cardiovascular disease risk as the pattern of fat accumulation.
However, in an accompanying editorial, Michael Criqui, M.D., M.P.H., professor of family and preventive medicine at the University of California, San Diego, said the EWET model proved to be a strong predictor because it focuses on high triglycerides. He notes that the NCEP definition of metabolic syndrome uses a triglyceride cutoff point of 150 mg/dL while the EWET used a lower cutoff point of 128 mg/dL. While the EWET model requires a woman to have both an enlarged waist and elevated triglycerides, the NCEP metabolic syndrome definition allows for normal values for any two of the five risk factors.
“What the EWET definition does is include all women with the highest risk component, triglycerides, while the NCEP metabolic syndrome definition doesn’t,” he said.
Criqui suggested that triglycerides, HDL and blood pressure be measured along with other independent CVD risk factors to provide the best estimate of CVD risk.
Tanko’s co-authors are Yu Z. Bagger, M.D.; Gerong Qin, M.D.; Peter Alexandersen, M.D.; Philip J. Larsen, M.D., Ph.D. and Claus Christiansen, M.D.
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