Sleep Duration, Sleep Quality and Physical Activity, but Not Sedentary Behaviour, Are Associated with Positive Mental Health in a Multi-Ethnic Asian Population: A Cross-Sectional Evaluation

Background: We assessed the associations of sleep, physical activity and sedentary behaviour with positive mental health (PMH) in the multi-ethnic population of Singapore. Methods: The Singapore Health 2 study is a nationally representative cross-sectional survey among residents aged 18–79 years. A PMH instrument was administered to 1925 participants to obtain total PMH and six sub-component scores. Self-rated sleep duration, sleep quality, sedentary behaviour and physical activity were assessed. Multivariable linear regression analyses were conducted. Results: The mean age of the participants was 40.1 (SD 14.3) years. Sleep duration (≥8 h/night: β = 0.17,95% CI: 0.02–0.32; 7–< 8 h/night: β = 0.17,95% CI: 0.03–0.30 versus <6 h/night, p = 0.002), sleep quality (very good: β = 0.45,95% CI: 0.29–0.60; fairly good: β = 0.20,95% CI: 0.06–0.33 versus very/fairly bad; p trend < 0.001) and physical activity (high: β = 0.19,95% CI: 0.05–0.32; moderate: β = 0.15, 95% CI: 0.03–0.27 versus low; p trend < 0.001) were directly associated with total PMH. Sedentary behaviour was not significantly associated with PMH. Sleep duration, sleep quality and physical activity were directly associated with the PMH sub-components ‘emotional support’ and ‘personal growth and autonomy’. Conclusions: Duration and quality of sleep and physical activity were directly associated with PMH in an urban Asian population. These findings support incorporating sleep and physical activity interventions to improve population mental health.