Physical Activity, BMI, and Diabetes Risk in the Physicians' Health Study

Physical activity lowers risk for diabetes, whereas being overweight or obese raises risk. In a prospective analysis from the Physicians' Health Study, researchers assessed the associations among activity levels, body-mass index, and incident diabetes in 20,000 men (mean age at enrollment, 53) without diabetes at baseline who were followed for a median of 23 years.

Overall, 9% of the cohort developed diabetes. Rates of incident diabetes among normal (BMI, <25 kg/m²), overweight (BMI, 25–29) and obese (BMI, ≥30) men were 2.4, 6.1, and 15 cases per 1000 person-years, respectively. Among normal-weight and overweight men, researchers noted a significant trend toward lower incidence of diabetes with progressively higher intensities of exercise. I…