International Journal of Physical Medicine & Rehabilitation
Open Access

Abstract

Physical Activity and the Prevention of Depression: A Longitudinal Analysis of a South African Database

Seranne Motilal*, Mike Greyling, Karestan C. Koenen, Mosima Mabunda, Dan J. Stein and Martin Stepanek

Background: Growing evidence suggests physical activity is a modifiable protective factor that may reduce risk of developing depression. However, research has predominantly come from high income settings, is often cross-sectional, may not address differences in levels of physical activity, and has not emphasized potential sex differences. Discovery is the largest private medical insurance provider in South Africa and its Health and Vitality database provides a unique resource for addressing these gaps.

Methods: This retrospective cohort study consisted of deidentified health and physical activity data containing 49,397 unique individuals from the period 2013-2015. Participants were categorized by change in physical activity level after 3 years and depression incidence was compared among these cohorts. Propensity scores were used to account for physical activity cohort selection factors. The analysis also tested for sex by cohort interaction and conducted stratified analyses by sex.

Findings: Females had almost double the incidence of depression as compared with males in the sample period. Post hoc tests for the interaction indicated that increased physical activity reduced risk of depression for females (F2, 49397=9.18, p<0.0001) but no significant affect was noted for males (F2, 49397=0.19, p<0.83). A small increase in physical activity showed a significant reduction of depression incidence in females.

Interpretations: The results extend previous findings on physical activity and depression to the South African population, finding increasing physical activity reduced depression for females. While the findings for males in the study were not statistically significant, prior research has shown that, for males, exercise may be an important preventative factor for depression.

Published Date: 2022-08-26; Received Date: 2022-07-21