Look to More Than BMI for Accurate Health Picture, Says UAB Prof

Being overweight is a health concern, and using only body mass index (BMI) to determine if someone is of a healthy weight may not give an accurate picture of someone’s health, according to an advisory published today in Circulation: Journal of the American Heart Association. University of Alabama (UAB) Professor of Preventive Medicine Cora E. Lewis, M.D., M.S.P.H., is lead author of the advisory.

June 8, 2009

BIRMINGHAM, Ala. - Being overweight is a health concern, and using only body mass index (BMI) to determine if someone is of a healthy weight may not give an accurate picture of someone's health, according to an advisory published today in Circulation: Journal of the American Heart Association. University of Alabama (UAB) Professor of Preventive Medicine Cora E. Lewis, M.D., M.S.P.H., is lead author of the advisory.

Lewis said a number of studies have examined the relationship between overweight as measured by BMI, and risk of death from all causes, but have had contradictory results. However, death from all causes overlooks the role that being overweight may play in the development of other risk factors for cardiovascular diseases, as well as in other conditions. 

The advisory, she said, recommends not only doing research on overweight and health (beyond studies that focus solely on the relationship between total BMI and risk of death), but also taking action now by promoting healthy eating and physical activity.

"What has been left out of the focus on death from all causes are the important relationships between BMI and other health outcomes, such as cardiovascular disease and its risk factors," Lewis said. "Arguably, the most important relationship among the cardiovascular disease risk factors is diabetes, which is significantly more common in overweight than in normal-weight people."

About one-third of the U.S. population is overweight. Overweight in adults is classified as a BMI of 25.0 to 29.9. BMI is a numerical value of weight in relation to height.

Lewis and her co-authors said part of the problem with quantifying the true impact of overweight lies in the way BMI is measured. It does not distinguish between fat mass that is related to important health concerns, such as type 2 diabetes, and lean mass, including muscle, which reduces health risks. Also, BMI does not directly measure the distribution of fat, such as whether there is greater fat at the waist than at the hips, which may be more detrimental to health.

"Weight gain is progressive and weight loss difficult," Lewis said. "No matter how it is measured, achieving and maintaining a healthy body weight should be of high importance for everyone."

Advisory co-authors include Kathleen M. McTigue, M.D., M.P.H.; Lora E. Burke, Ph.D., M.P.H.; Paul Poirier, M.D., Ph.D.; Robert H. Eckel, M.D.; Barbara V. Howard, Ph.D.; David B. Allison, Ph.D.; Shiriki Kumanyika, Ph.D., M.P.H.; and F. Xavier Pi-Sunyer, M.D. 

About UAB

The UAB Division of Preventive Medicine is dedicated to medicine and the health of the public through research, teaching and dissemination and translation of knowledge for improved health outcomes. From its inception in 1967, the division has played a key role in the many groundbreaking trials contributing to the knowledge of medical and health systems, behavioral aspects of disease, epidemiology, prevention, control, and disease outcomes. Special concern for health disparities and a desire to promote women's health guide many division activities. A research-oriented division, it also has active programs for the training of post doctoral fellows and clinical scholars.