BMI and waist size predict pre-diabetic state

Both body mass index (BMI) and waist circumference appear to be useful in predicting cardiovascular risk and metabolic abnormalities in people who are insulin resistant, a prediabetic condition, according to Californian researchers.

Dr. Gerald M. Reaven and colleagues at Stanford University School of Medicine hypothesized that BMI, the ratio of weight to height, and waist circumference might be equally effective in identifying insulin-resistant patients with cardiovascular disease risk factors.

To investigate further, the researchers examined 261 apparently healthy volunteers who had responded to advertisements about the study. Of this group, 133 were classified as obese, defined as having a BMI of 30 or greater.

As reported in the American Journal of Cardiology, the team found that several metabolism factors worsened as a function of increased obesity. Some of these included insulin sensitivity, a prediabetic condition in which normal insulin levels do not produce an adequate insulin response, and related metabolic cardiovascular risk factors, such as elevated triglycerides.

This was true regardless of whether BMI or waist circumference was used as the measure of excess fat.

However, increases in total and "bad" LDL cholesterol and decreases in "good" HDL-cholesterol concentrations were seen only in subjects with higher BMI values.

Summing up, Reaven told Reuters Health that it appears that "either BMI or waist circumference can be used by clinicians to help indicate whether a particular patient may be insulin resistant and at increased cardiovascular risk."

"However," he concluded, "since most patients have their height and weight determined when they see a physician, and it is easy to calculate BMI from these simple measurements, why not just stick with BMI?"

SOURCE: American Journal of Cardiology, October 15, 2006.