Testing bidirectional relationships between marital quality and sleep disturbances: a 4-year follow-up study in a Korean cohort.

OBJECTIVE Both poor marital quality and sleep disturbances are risk factors for a broad range of mental and physical health morbidities. The purpose of the study was to investigate bidirectional relationships between marital quality and sleep disturbance and the moderating effects of age and gender. METHODS Data from 1081 married individuals who participated in the Korean Genome and Epidemiology Study were analyzed. A marital quality questionnaire and the Pittsburgh Sleep Quality Index were used to assess marital quality and sleep disturbances at baseline and 4-year follow-up. Relevant covariates including sociodemographics, health status, health behaviors, and depressive symptoms were also measured. RESULTS Hierarchical multiple regression models revealed that there was a significant interaction between marital quality and age predicting sleep disturbance (P=.017). While there was no association between marital quality and sleep disturbances for the younger group (ages 45-54; n=680), persons with lower marital quality were more likely to have greater sleep disturbances 4 years later for the older group (ages 55-74; n=401). By contrast, sleep disturbance was a significant predictor of marital quality 4 years later, regardless of age or gender (P=.025). CONCLUSION Poor marital quality is a risk factor for sleep disturbance for older adults but not for middle-aged individuals. In turn, sleep disturbance may lead to lower marital quality for all age groups. Clinicians should be aware of the bidirectional relationships between marital and sleep problems for more effective treatments for both.