Relationship of dietary factors and habits with sleep-wake regularity.

The purpose of this study was to evaluate the associations between dietary factors and sleep-wake regularity in the Japanese population. We analyzed 1368 eligible subjects (931 men and 437 women) aged 35-69 years who had participated in the baseline survey of a cohort study in Tokushima Prefecture, Japan. Information on individual lifestyle characteristics, including dietary habits and sleep-wake regularity, was obtained by a self administrated questionnaire. Logistic regression analyses were performed to evaluate adjusted associations of the intake energy ratios of macronutrients, as well as intake frequency, and the amount of staple foods with sleep wake regularity. The lowest quartile of protein intake as well as the highest quartile of carbohydrates showed significantly higher multivariable-adjusted odds ratios of 2.1 (95% confidence interval, 1.3-3.3) and 2.1 (1.3-3.5), respectively, for poor sleep-wake regularity compared with the respective second quartile that is thought to be moderate intake. Regarding intake of staple foods, low weekly intake frequency at breakfast (<5 times/week), the lowest intake amount (<1 bowl or slice/roll) at breakfast, and the highest intake amount (>=2 bowls or slices/ rolls) at lunch and dinner exhibited significantly high adjusted odds ratios for poor sleep-wake regularity. Additionally adjusting for sleep duration, these results did not substantially alter. Our results suggested that low intake energy ratio of proteins and high intake energy ratio of carbohydrates, skipping intake of the staple foods at breakfast, and excessive intake amount of the staple foods at lunch and dinner may be associated with poor sleep-wake regularity.