Association between Nocturnal Sleep Duration and Insomnia symptoms with depressive symptoms among 44,900 Chinese Han adults aged 30-79 in Southwest China.

Background: Although there are several cross-sectional and prospective studies on the relationship between sleep duration /insomnia symptoms and depression symptoms, the results of these studies are still not conclusive, and few studies have further analyzed the association between sleep duration and depressive symptoms in adults by gender and age. Thus, this study aimed to investigate the relationship between nocturnal sleep duration and insomnia symptoms with depression symptoms, and further examine whether the association was impacted by age and gender in a large-scale Han Chinese population in southwest China.

Methods: A cross-sectional study was performed that included 44,900 participants from 18 districts in southwest China from September 2018 to January 2019. The study comprised 42,242 individuals in the final analysis. Depressive symptoms were investigated using the PHQ-2 questionnaires. Multivariate logistic regression analysis was performed to investigate the relationship between nocturnal sleep duration and insomnia symptoms with depression symptoms as well as the influence of age and gender.

Results: After adjusting for multiple variables, those with nocturnal sleep duration < 7 h had a higher odds ratio for depression (OR:1.47, 95%CI 1.31-1.65) compared to participants whose nocturnal sleep duration was in the range of 7-8 h. Notably, there is a higher association in those aged below 45 years (OR:1.91, 95%CI 1.52-2.41) and in female participants (OR:1.57, 95%CI 1.35-1.82). However, nocturnal sleep duration longer than 9 h was not associated with depression symptoms in either the whole population analysis or the subgroup analysis. Insomniacs had a higher odds ratio for depression(OR:1.87, 95%CI 1.84-2.36, respectively) compared to non-insomniacs. There is a higher association in those aged 45-60 years (OR:2.23, 95%CI 1.82-2.73) and in female participants (OR:2.17, 95%CI 1.84-2.56). Further subgroup analysis by age and gender at the same time showed the association between sleep deprivation and depression was highest among women aged below 45 years, while the association between insomnia and depression was the highest among men aged 45-59 years.

Conclusion: Short nocturnal sleep duration and insomnia symptoms were positively associated with the risk of depressive symptoms among Chinese Han adults aged 30-79 in Southwest China, especially the middle-aged population and females should be more concerned.