Adherence to the Japanese Food Guide and chronic insomnia among Japanese male truck drivers: a cross-sectional study.

Chronic insomnia is common among truck drivers and is associated with an increased risk of road traffic accidents. However, evidence linking diet quality to insomnia in Japanese working populations remains limited. This cross-sectional study examined the association between adherence to the Japanese Food Guide (JFG) and chronic insomnia among 1,942 male Japanese truck drivers. Dietary intake was assessed using the Brief-type Diet History Questionnaire, and diet quality was evaluated using a modified JFG score. Chronic insomnia was defined according to ICSD-3. Chronic insomnia prevalence was 20.2%. In multivariable logistic regression analyses adjusting for sociodemographic, lifestyle, occupational and psychological factors, participants in the highest JFG adherence quartile had lower odds of chronic insomnia than those in the lowest quartile (OR 0.69, 95% CI 0.49-0.97, p=0.034). No significant associations were observed for the second or third quartiles, and the linear trend was not significant (p for trend=0.056). Psychological distress was the strongest factor associated with chronic insomnia, but no significant interaction with JFG adherence was observed. Greater adherence to the Japanese Food Guide remained independently associated with lower odds of chronic insomnia, suggesting that diet quality may complement workplace mental health strategies.