Age Disparities in the Association Between Leisure-Time Physical Activity and Depression Among American Adults

This study aims to investigate the association between leisure-time physical activity (LTPA), age, and depressive symptoms.

We included and analyzed data from 18,052 participants (age ≥ 20 years) from the cross-sectional National Health and Nutrition Examination Survey (NHANES) (2007-2014). Multivariable logistic regression was employed to assess the independent associations between physical activity and household income with depressive symptoms. Restricted cubic spline plots were utilized to analyze the non-linear relationship between LTPA and depression.

Among the 18,052 participants, 1,676 (9.28%) were defined as having depressive symptoms. We found: 1. Age exhibits a non-linear relationship with depression, with a turning point around 40 years. 2. Compared to those with no LTPA, individuals with higher levels of LTPA (Q3) in both younger and older age groups experienced the lowest risk of depression, with risk reductions of 53% (odds ratio [OR] 0.47, 95% confidence interval [CI] 0.33-0.67) and 74% (OR 0.26, 95% CI 0.14-0.50), respectively. Conversely, in the middle-aged group, those with the highest level of LTPA (Q4) experienced the greatest reduction in depression risk, by 67% (OR 0.33, 95% CI 0.21-0.53). 3. A U-shaped relationship between LTPA and depression risk was observed in younger and older age groups.

The risk of depression peaks around the age of 40 in adults. For middle-aged individuals, greater engagement in LTPA is associated with reduced depression risk. Conversely, higher levels of LTPA in younger and older adults may not confer additional protective effects.