Optimal body mass index for minimizing the risk for osteoporosis and type 2 diabetes

Body mass index (BMI) is positively associated with bone mineral density and type 2 diabetes. We investigated an optimal BMI range for osteoporosis and type 2 diabetes.

This cross-sectional study used data from the Korea National Health and Nutrition Examination Survey (KNHANES), 2008 to 2011. We included 3,774 men aged > 50 years and 4,982 postmenopausal women. Logistic regression models were applied to elucidate each BMI category's osteoporosis and diabetes risks.

The prevalence of osteoporosis was 9.0% for men and 40.8% for women. The prevalence of type 2 diabetes in men was 19.7% and in women was 15.5%. In men with BMI > 25 kg/m2, the osteoporosis risk did not further increase as BMI increased. In women, BMI was linearly associated with osteoporosis risk without a plateau. In both men and women, higher BMI was associated with a higher type 2 diabetes risk. Men with a BMI of 23.0 to 24.9 kg/m2 harbored about a 30% lower osteoporosis risk than and a similar diabetes risk to those with a BMI of 21.0 to 22.9 kg/m2. In women with a BMI of 23.0 to 24.9 kg/m2, the adjusted odds ratio for osteoporosis was 0.72 (95% confidence interval, 0.59 to 0.87); the diabetes risk was not higher than in those with a BMI of 21.0 to 22.9 kg/m2.

For Korean men aged > 50 years and postmenopausal women, a BMI of 23.0 to 24.9 kg/m2 was the optimal range for minimizing osteoporosis and type 2 diabetes risks simultaneously.