The Epidemiology of Depressive Symptoms and Poor Sleep: Findings from the English Longitudinal Study of Ageing (ELSA)

PURPOSE The reasons for the comorbidity between depressed mood and poor sleep are not well understood. METHOD Participants were 5172 adults aged 50 years and older from the English Longitudinal Study of Ageing. Sleep was measured via self-report and depressive symptoms using the Centre for Epidemiological Studies Depression scale. RESULTS Greater depressive symptoms and sleep complaints were associated with female sex, non-cohabitation, relative poverty, smoking, infrequent physical activity, infrequent alcohol consumption, higher body mass index (BMI), diagnosis of hypertension, coronary heart disease, diabetes/high blood glucose, pulmonary disease, arthritis, and higher levels of fibrinogen and C-reactive protein (all p < 0.05). At a 4-year follow-up, depressive symptoms and sleep complaints were both predicted by baseline depressive symptoms and sleep complaints, relative poverty, smoking, physical inactivity, BMI, and arthritis (all p < 0.05). CONCLUSION Depressive symptoms and sleep complaints share a range of correlates cross-sectionally and prospectively. These findings highlight the common comorbidity between depressive symptoms and sleep complaints underscoring the need for further research to understand their combined detrimental effect on long-term health and wellbeing.