Population attributable risk of excess weight, abdominal obesity and physical inactivity for type 2 diabetes in Chinese men and women.

Background: Given the high prevalence of type 2 diabetes mellitus (T2DM) in the Chinese population, it is necessary to estimate the T2DM incident attributable to obesity and physical inactivity.

Methods: We analyzed the data from the Shanghai Men's and Women's Health Studies, including 56,691 men and 70,849 women aged 40-74. The hazard ratios (HRs) and the population attributable risks (PARs) were calculated by Cox regression model and model-based estimation.

Results: A total of 3,315 male and 5,925 female cases were identified during 519,157 and 981,504 person-years, up to 31 December 2017. Excess weight, abdominal obesity were associated with the increased risks of T2DM both in women and men, while physical inactivity was only associated with an increased risk in men. A large proportion of T2DM incident cases can be attributed to excess body weight (women: 48.6%; men: 41.5%) and abdominal obesity (women: 50.4%; men: 30.3%). Physical activity was negatively associated with the risk of T2DM (P<0.01). The PARs adjusted for confounders were 3.6% for physical inactivity in men and 1.7% in women.

Conclusions: Excess weight and abdominal obesity accounted for a large proportion of T2DM incident cases in men and women; a small part of T2DM cases were attributed to physical inactivity in men. Weight control is of great significance in curbing the epidemic of diabetes.