Obesity Paradox Called into Question

A new study finds that the “obesity paradox”—the rate of mortality is lower among diabetes who are overweight or obese as compared to those who are normal weight—does not exist.

Researchers looked at 11,427 participants with incident diabetes, pulled from the Nurses’ Health Study and the Health Professionals Follow-Up Study, who were free of cardiovascular disease and cancer at the time of a diagnosis of diabetes.

BMI was calculated using the body weight and height shortly before diagnosis. During the 15+ year follow-up, 3083 participants died. Compared with normal-weight participants (BMI of 22.5-24.9), underweight participants with a BMI of 18.5-22.4 (hazard ratio, 1.29) and those with BMIs of 30 or above, considered “obese,” had significantly increased mortality risks (hazard ratio, 1.24).

The highest risk was for the “severely obese” participants with BMIs of 35 or higher (hazard ratio, 1.33). Researchers observed a J-shaped association between BMI and mortality among all participants, as well as among those who had ever smoked; there was a direct linear relationship among those who had never smoked.

The complete study is available in the New England Journal of Medicine.

Reference:

Tobias D, Pan A, Jackson C, et al. Body-mass index and mortality among adults with incident type 2 diabetes. N Eng J Med. 2014 Jan 16. doi: 10.1056/NEJMoa1304501