Physical activity and reduced risk of depression: Results of a longitudinal study of Mexican adults.

Abstract

To evaluate the effect of physical activity (PA) on the risk of depression among Mexican adults over a 6-year follow-up period. We evaluated longitudinal data from the Health Worker Cohort Study, which follows employees of the Mexican Institute for Social Security in Morelos State, Mexico, over time. Depressive symptoms and PA were assessed at baseline and at a follow-up measurement 6 years later. The study population was free of depressive symptomatology at baseline, as assessed by the Center for Epidemiological Studies-Depression Scale (CES-D). After 6 years, the CES-D was completed once again by the participants to estimate their risk of depression based on the different PA patterns they reported during the follow-up period. PA was estimated using a questionnaire that has been applied in similar longitudinal studies and has been validated in Spanish, with metabolic equivalents (METs) as the unit of measurement. We identified three PA patterns: highly active, moderately active, and inactive. The relative risk of depression (CES-D score ≥ 16 points) was estimated using multivariate logistical regression analysis according to the PA patterns at a follow-up measurement 6 years later. The incidence of depression after 6 years was higher among inactive participants (16.5%) than among those with an active PA pattern (10.6%). We found that more active PA patterns have an important protective effect against depression. The odds ratio (OR) for the more active PA patterns was 0.46, 95% confidence interval (CI) [0.25, 0.87], and for individuals with a moderately active PA pattern, the OR was 0.57, 95% CI [0.34, 0.93]. These ORs were obtained after adjusting for confounding variables and baseline PA levels. Our results indicate that PA may reduce risk of depression in Mexican adults. These findings have potential applications for depression prevention programs in target populations with similar social and cultural contexts.