A little hard to digest

Two new studies tell us that metabolic syndrome, not BMI, is linked to cardiovascular events and outcomes in women

By raymond Reese

Traditionally, obesity has been a prime focus in assessing the risk for cardiovascular disease (CVD). Studies now show that determining whether someone's metabolism is humming happily or limping along is a more accurate predictor of CVD risk than obesity. These findings are from the Women's Ischemia Syndrome Evaluation (WISE) study, reported in two new studies in the February 17 issue of Circulation.

The studies demonstrate that women with metabolic syndrome -- a combination of health risks that includes having too much abdominal fat, high blood pressure and blood sugar levels, and low levels of 'good' high density lipoproteins (HDL) cholesterol -- are more at risk for CVD than obese women with a normal metabolism.

The first study, headed by Dr Steven Reis of the University of Pittsburgh, looked at 780 women who were suspected to have myocardial ischemia. The researchers compared the prevalence of significant angiographic coronary artery disease (CAD) -- the build up of artery-clogging, stroke-inducing cholesterol -- and the 3-year risk of CVD to body mass index (BMI) and metabolic status in the women. Using BMI criterion, 184 women were found to be of normal weight, 369 overweight, and 327 obese. Metabolic syndrome or diabetes (a frequent companion of the syndrome) was present in 451 women and absent in 329. The women of normal weight who didn't have metabolic syndrome or diabetes formed the control group. Both groups were matched in terms of age, race, menopausal activity, and physical activity.

When compared to the controls, women of normal weight with metabolic syndrome or diabetes were found to be almost twice as likely to have a 50% blockage of a coronary artery in the future. Obese women with metabolic syndrome were over three times as likely to be headed for trouble. The researchers found that "metabolic syndrome and BMI were strongly associated, but only metabolic syndrome was associated with significant CAD." The surprising finding was that obese women whose metabolism was normal were not any more at risk for CVD than women of normal weight.

The take home message, according to the researchers, is that though recommending weight loss for obese and overweight women is prudent, preventing development of metabolic syndrome in all women, regardless of weight, should be the ultimate goal.

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In the second study, another team working under Dr Reis also looked at women from the WISE study, but from a slightly different perspective, focusing more closely on CAD.

Among 755 women with suspected myocardial ischemia, 25% had metabolic syndrome. These women had a markedly lower four-year survival rate from major adverse cardiovascular events, compared to women whose metabolism was normal (94.3% versus 97.8%). When the women's long term fortunes were expressed mathematically in a calculation known as the hazard ratio, those women with both angiographically significant CAD and metabolic syndrome, were about 3.5 times as likely to suffer misfortune in the next four years as women who had CAD but not metabolic syndrome.