Sleep duration and incident and persistent depressive symptoms among a rural ageing population in South Africa

Background: The aim of the study was to assess the relationship between sleep duration and incident depressive symptoms (IDS) and persistent depressive symptoms (PDS) using longitudinal data from South Africa. Methods: This longitudinal community study enrolled 3891 adults (≥40 years) from the “Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI)”. Sleep duration was assessed by self-report at wave 1, and depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale at wave 1 and 2. Outcomes were incident and persistent depressive symptoms at wave 2. Multivariable logistic regression analysis was conducted to assess the associations between sleep duration at wave 1 and incident, and persistent depressive symptoms. Results: The prevalence of IDS was 25.6% and PDS 30.8%. The prevalence of very short, short, normal, and long sleep duration at baseline was 3.6%, 10.1%, 60.9% and 25.4%, respectively. In the fully adjusted model, long sleep duration was positively associated with IDS among men (AOR: 1.37, 95% CI: 1.02–1.84), but not among women (AOR: 0.91, 95% CI: 0.67–1.23). No models among both men and women showed a significant association between short sleep and IDS. Long sleep duration was associated with PDS (AOR: 2.04, 95% CI: 1.20–3.48) among men but not among women (AOR: 1.26, 95% CI: 0.76–2.11). Short sleep showed among both sexes no significant associations with PDS. Conclusion: Long but not short sleep duration was independently associated with IDS and PDS among men but not among women.