Sex-Specific Moderation Effect of Age on the Associations Between Insomnia Symptoms and Various Psychological Distresses

Background: Insomnia is closely related to psychological distress. This study aims to examine the role of age and sex in the association between various psychological distresses and insomnia symptoms. Participants and Methods: This population-based study used data provided by cumulative respondents of the annual survey of the Taiwan Suicide Prevention Center between 2006 and 2019. Potential respondents were aged >= 15 years and were selected by a stratified proportional randomization method according to the distribution of population size, sex, and age in different geographic areas of Taiwan. The Five-Item Brief Symptom Rating Scale was used to measure insomnia symptoms and four psychological distresses: depression, anxiety, hostility, and inferiority. The independent relationship between insomnia symptoms with depression, anxiety, hostility, and inferiority was further examined according to age and sex. Results: A total of 28,649 participants were included (women, 50.2%). The four types of psychological distress correlated differentially with insomnia symptoms. Concerning interaction effects, sex moderated the interaction effects between age with depression, anxiety, and hostility. In men, and not in women, age moderated the relationship between insomnia symptoms and all four psychological distresses. Specifically, the effect sizes of the associations between insomnia symptoms and depression, anxiety, and hostility showed an age-dependent decreasing trend in men. Conclusion: The associations between psychological distresses and insomnia symptoms varied in strength and according to age in a sex-specific manner.