In some people, obesity interacts with inherited factors and leads to the onset of insulin resistance. This metabolic abnormality in turn is responsible for altered glucose metabolism and a predisposition to type 2 diabetes. In addition, it causes a number of subclinical abnormalities that predispose to cardiovascular disease and accelerate its onset. The most important among these are type 2 diabetes, dyslipidemia, and hypertension. When clustered together with other insulin resistance–related subclinical abnormalities, these are referred to as the metabolic syndrome (Abate, 2000). Virtually all obese women with hypertension demonstrate elevated plasma insulin levels. Levels are even higher in women with excessive fat in the abdomen—an apple shape, compared with those whose fat is in the hips and thighs—a pear shape (American College of Obstetricians and Gynecologists, 2003). In fact, Gus and associates (2004) reported that for women, a waist circumference greater than 88 cm was more predictive of hypertension than a BMI greater than 30 kg/m2.
Criteria used by the National Institutes of Health (2001) to define the metabolic syndrome are shown in Table below. Of interest, the American Diabetes Association eschews the "syndrome" designation and urges consideration for these and other cardiovascular-disease risk factors that occur singly or in combination (Kahn and colleagues, 2005).
aThose with normal values while taking medications are considered to meet these criteria.
Williams Obstetrics 23rd Edition (McGraw-Hill) 2009