Waist size key to predicting health risk

BOSTON (Reuters) — A large European study has confirmed that simple measurements of the waist and hips may offer a better way of predicting obesity-related death than a standard, but more complicated, system of relating weight to height.

The standard body mass index, or BMI, method does not work very well for some people, such as the elderly or body builders, and researchers have begun building a case that it is better to look at waist circumference or the ratio of waist size to hip size. Among people with comparable BMIs, having an extra two inches around the waist increased the annual risk of death by 17 percent for men and 13 percent for women, according to the team led by Dr. Tobias Pischon of the German Institute of Human Nutrition Potsdam-Rehbruecke in Nuthetal, Germany.

When they calculated the waist-to-hip ratio by dividing a person's waist size, measured at the navel, by the biggest part of their hips, the Pischon group found that the risk of death increased by 34 percent for men and 24 percent for women every time that ratio increased by 0.1.

Hip circumference alone did not predict death any better than BMI, which is a person's weight in kilograms divided by the square of the height in metres, the researchers found.

They used data from the European Prospective Investigation into Cancer and Nutrition database, involving 359,387 people in nine countries. Men with the biggest bellies had more than twice the death rate of the slimmest. For women, the rate was 79 percent higher if their weight was in the normal range yet their bellies were big.

The findings, published in the New England Journal of Medicine, "underscore the importance of assessing the distribution of body fat even among persons of normal weight and challenge the use of cut-off points to define abdominal obesity, at least when they are used to predict the risk of death," the researches wrote.