The association between milk and dairy products intake and insomnia symptoms among Japanese adults in community-based cohort

Abstract

Objective: To examine the association between habitual intake of milk and dairy products and insomnia. Design: Cross-sectional study by using cohort study data among 60,633 participants (22,721 men and 37,912 women) aged 20–74 years in eastern Japan. The data of milk and dairy products intake, sleep status and other lifestyle habits were collected by self-administered questionnaires. The question about milk and dairy products included whole milk, low-fat milk, cheese, yogurt, and lactic acid bacteria beverages, and were assessed by frequency (< 1 time/week, 1–2 times/week, 3–6 times/ week, and ≥ 1 time/day). Sleep status was scored with the Athens Insomnia Scale. Results: Logistic regression analysis showed that adjusted odds ratio (OR) and 95% confidence interval (95% CI) for insomnia were statistically significantly lower for whole milk intake > 1 time/day compared to < 1 time/week in all (OR: 0.91; 95% CI: 0.86–0.96; P = 0.001). The similar results were shown for women (OR: 0.90; 95% CI: 0.85–0.97; P = 0.002), not for men. In contrast, the adjusted odds for insomnia were high in the group that had frequencies of 3–6 times/week of lactic acid bacteria beverages compared to <1 time/week (OR: 1.20, 95% CI: 1.11–1.29; P < 0.001 in all; OR: 1.36; 95% CI: 1.19–1.55; P < 0.001 in men; OR: 1.13; 95% CI: 1.03–1.24; P = 0.009 in women). Conclusions: This cross-sectional study of Japanese populations showed a tendency for no insomniacs to consume whole milk more frequently.