Alcohol drinking patterns and sleep quality of Japanese civil servants

OBJECTIVE: The purpose of this study was to clarify whether alcohol drinking patterns were associated with sleep quality. METHODS: A cross-sectional survey was carried out by self-administered questionnaire in 2008 among 2,118 employees aged 18 to 65 years working in local government in Toyama. After excluding those without relevant data for this study, 661 men and 618 women represented the study population. Logistic regression analysis was used to evaluate whether alcohol drinking patterns (as measured by the frequency, the amount of alcohol per day and the timing of alcohol drinking) were associated with poor sleep quality (as measured by the Pittsburgh Sleep Quality Index), after adjustment for potential confounding factors: age, family structure, work characteristics (as measured by the job-demand-control-support model, shift work and occupational class), chronic disease, body mass index, smoking status and physical activity. RESULTS: In comparison with men who did not drink, the adjusted odds ratio for poor sleep quality was 0.52 (95%confidence interval: 0.32-0.85) for those who drank alcohol once a week or more, 0.32 (0.13-0.84) for those who drank 1-3 glasses daily, 0.30 (0.13-0.70) for those who drank 7-14 glasses per week, 0.37 (0.17-0.77) for those who drank only at meals. In women, the drinking patterns were not significantly associated with sleep quality. CONCLUSIONS: The results of this study suggest that some alcohol drinking patterns may affect sleep quality among men who do not use sleeping medicine.