Physical activity and common mental disorders: results from the Caerphilly study

The authors examined associations between leisure-time and occupational physical activity and common mental disorder (CMD), defined as anxiety and depression, using data from a cohort of middle-aged men in Caerphilly, South Wales, United Kingdom, who were followed for 5 years (1989-993) and 10 years (1993-1997). CMD was measured using the General Health Questionnaire. Total leisure-time activity and percentage of time spent in heavy-intensity activity were estimated from self-reports (Minnesota Leisure Time Physical Activity Questionnaire). Men were classified into four classes of occupational activity. Among 1,158 men with complete data, those who participated in any heavy-intensity leisure-time activity had reduced odds of CMD 5 years later (below median vs. none: adjusted odds ratio (OR_adj) = 0.61, 95% confidence interval (CI): 0.40, 0.93); median or above vs. none: OR_adj = 0.54, 95% CI: 0.35, 0.83). Analyses using multiple imputation to deal with missing data found weaker evidence for an association (OR_adj = 0.79 (95% CI: 0.54, 1.15) and OR_adj = 0.73 (95% CI: 0.49, 1.09), respectively). There was little evidence that men in the most physically demanding jobs had reduced odds of CMD after 5 years, and there was no association between physical activity and CMD 10 years later. Among these men, heavy-intensity leisure-time physical activity was associated with a small reduction in CMD over 5 years.