Sleep quality as a mediator of the association between coping styles and mental health: a population-based ten-year comparative study in a Chinese population

Backgrounds: Little is known about the variation in sleep quality and its association with coping style and mental health in 21st century China, despite of enormous socioeconomic changes. This study aims to document the variation in sleep quality and its contribution to the association between coping style and mental health in China.Methods: Pooled cross-sectional data of 46,561 adults was obtained from the 2004 and 2015 mental health surveys conducted in Shandong Province, China. A Simplified Coping Style Questionnaire and the Pittsburgh Sleep Quality Index were assessed, with mental health measured by the General Health Questionnaire (GHQ). A mediation regression model was run to test the mediating effect of sleep quality.Results: Above 10% reported poor sleep quality or median-to-high risk of mental disorders according to GHQ results in year 2015, and a significant but small improvement for sleep quality and mental health came during the studied decade, with the exception of poor sleep quality increasing among males. In 2015, a one-point increase in sleep quality score was associated with an increase of 0.17 (95% CI, 0.16-0.18) and 0.16 (95% CI, 0.140.17) points on the GHQ for males and females, respectively. Sleep quality mediated the relationship between negative tendency of coping style and elevated GHQ scores, and the mediating effects grew stronger in 2015 than those in 2004.Limitation: The study is a cross-sectional study, and the sample is not nationally representative.Conclusion: An integrative intervention of mental health promotion is recommended to account for sleep quality and coping strategies..