Physical activity and type 2 diabetes risk

Clinical evidence increasingly identifies individuals with severe mental disorders as a population exhibiting markedly elevated susceptibility to diabetes and its associated complications. Within this context, physical inactivity and prolonged sedentary behavior emerge as prominent, modifiable risk factors contributing to type 2 diabetes mellitus (T2DM). However, a critical gap persists regarding whether obesity and age significantly modify the protective association of physical activity (PA) and T2DM, and the precise nature of this dose–response relationship remains inadequately characterized. We analyzed cross-sectional data from 5042 adult participants in the 2017–2020 National Health and Nutrition Examination Survey (NHANES). We applied weighted multivariable logistic regression models to evaluate the PA-T2DM association. Furthermore, to delineate the dose–response relationship, we utilized restricted cubic splines (RCS), specifically testing for potential effect modification by body mass index (BMI) and age. After comprehensive adjustment for confounders, our analysis indicated that higher PA levels were independently correlated with a reduced T2DM risk. RCS dose–response analysis revealed nuanced effect modification patterns. Specifically, PA’s protective effect demonstrated a clear “BMI gradient” – most pronounced in normal-weight individuals, somewhat attenuated in the overweight group, and absent in participants with obesity. Concurrently, an “age stratification” pattern emerged; the association was strongest in middle-aged adults, exhibited a borderline significant trend among younger adults, and showed no significant association in older adults. Our findings suggest that the protective effect of PA against T2DM is modified by obesity and age. Consequently, future preventive strategies should evolve from universal PA recommendations toward more precise, stratified guidance that incorporates individual BMI and age profiles. This approach appears particularly relevant for integrated care models targeting high-risk populations, such as individuals with mental disorders.