Do men develop type 2 diabetes at lower body mass indices than women?

Abstract

Aims/hypothesis: To describe the associations between age, sex and BMI at diagnosis of type 2 diabetes, and test the hypothesis that men are diagnosed with diabetes at lower average BMI than women of similar age. Methods: Linear regression was used to estimate and compare the relationship between age and BMI at diagnosis among 51,920 men and 43,137 women included in a population-based diabetes register in Scotland for whom an index BMI measurement was taken within 1 year of diabetes diagnosis. We also examined HbA 1c values by sex within the same timescale. Results: Mean BMI closest to date of diagnosis of type 2 diabetes mellitus was 31.83 kg/m 2 (SD 5.13) in men and 33.69 kg/m 2 (SD 6.43) in women. The inverse relationship between age and BMI at diagnosis of type 2 diabetes mellitus was significantly steeper in women than in men (slope estimate in men -0.12 kg/m 2 per year [95% CI -0.13, -0.12] women -0.18 kg/m 2 per year [95% CI -0.18, -0.17], p<0.0001 for formal test of interaction). Mean BMI difference was most marked at younger ages and narrowed with advancing age. However, HbA 1c levels within 1 year of diagnoses were broadly similar in men and women. Conclusions/interpretation: Men are diagnosed with type 2 diabetes at lower BMI than women across the age range. This observation may help explain why type 2 diabetes is more common among middle-aged men in populations of European extraction. Whether the same pattern is also observed in other ethnic groups requires confirmation. © 2011 Springer-Verlag.