Health Effects of Overweight and Obesity in 195 Countries.

To the Editor: The Global Burden of Disease (GBD) collaborators (July 6 issue)1 report that more than two thirds of deaths related to high body-mass index (BMI) were due to cardiovascular disease, which suggests that BMI-defined obesity has a major effect on cardiovascular disease. Some readers may wonder whether the perceived burden of obesity could have been even larger if an accurate measure of body fat, instead of BMI, had been used. Data from the Aerobics Center Longitudinal Study, involving 30,000 persons assessed with a state-of-the-art method to determine adiposity, suggest that this may not be the case.2 We observed that BMI had a significantly higher discriminating capacity than bodyfat percentage or fat-mass index for predicting mortality from cardiovascular disease, and our study provided a physiological explanation for this finding. Our data also strongly support the use of BMI for defining obesity at an epidemiologic level, particularly in relation to mortality from cardiovascular disease. Furthermore, these findings suggest that obesity may be defined as an excess of body weight according to height (high BMI), rather than as an excess of body fat (high body-fat percentage or fat-mass index), as is generally stated.3