Associations between nutritional adequacy and insomnia symptoms in Japanese men and women aged 18-69 years: a cross-sectional study.

OBJECTIVES: Sleep and diet are important lifestyle factors for maintaining health. Although previous studies have suggested that sleep quality may be associated with specific nutrient and food intakes, the relationship between nutritional adequacy and sleep quality remains unclear. The purpose of this study was to examine the relationship between sleep quality (insomnia symptoms) and adequate nutrient intake among Japanese adults. DESIGN: Cross-sectional. SETTING: Nationwide population survey conducted in 2013. PARTICIPANTS: 1,997 participants (940 men and 1,057 women) aged 18-69 years. MEASUREMENTS: Insomnia symptoms were assessed using the Athens Insomnia Scale (AIS) and participants were classified into three groups (absent, minor, and moderate-severe) based on the total AIS score. Dietary intake was estimated using a questionnaire and nutrient intake adequacy was evaluated by comparing the self-reported intake with two indices of the Dietary Reference Intakes for Japanese (2015): an estimated average requirement (EAR) and tentative dietary goal for preventing lifestyle-related disease (DG). RESULTS: A total of 205 men (21.8%) and 266 women (25.2%) were categorized as having moderate-severe insomnia symptoms. Among men, moderate-severe symptoms were associated with higher prevalences of inadequate intakes of total dietary fiber, vitamin C, and zinc. However, there was little association between inadequate nutrient intake and insomnia symptoms among women. The number of inadequate nutrients was significantly associated with insomnia symptoms in men (DG, P=0.004; EAR, P=0.003) but not in women. CONCLUSIONS: This study suggested that insomnia symptoms may be associated with nutritional inadequacy in Japanese adults, especially among men.