Interactions between physical activity and psychological factors in the association with the risk of lean type 2 diabetes mellitus.

Background: The extent to which physical activity and psychological factors may affect the risk of diabetes mellitus among lean individuals remains unclear. Purpose: This study aimed to investigate the associations of total physical activity (TPA) and psychological factors with lean type 2 diabetes mellitus (T2DM) risk. Research Design: A prospective cohort study. Study Sample: The study population included 1,945 Korean adults who maintained a body mass index <23 kg/m 2 . Data Collection and Analysis: Baseline data on TPA and psychological factors were collected and T2DM incidence was assessed for 10 years. For analysis, a multivariable Cox proportional hazards regression model was used. Results: TPA was inversely associated with T2DM risk and this association was more pronounced in participants who were depressed or distressed; the top TPA quartile exhibited significant reductions in T2DM risk of 66% (95% confidence interval [CI]: 0.15, 0.78) and 65% (95% CI: 0.14, 0.88) among participants who reported depressed mood and those who perceived high distress, respectively, compared with the bottom TPA quartile. Conclusions: The current study demonstrated the preventive effects of physical activity on T2DM in lean adults through its interaction with psychological factors.