Short-term and long-term associations with sleep onset latency in school children in Japan

This study aims to examine the relationships between sleep onset latency and multiple sleep-related factors of seventh and tenth graders during the transition from childhood to adolescence.

Regarding sleep onset latency, we examined the short-term associations in Phase IV (2002) and long-term associations in Phase V (2005) of the Toyama Birth Cohort Study. In total, 4,673 boys and 4,694 girls in Phase IV and 2,969 boys and 3,108 girls in Phase V answered the questionnaire items regarding sleep, physical and mental health, lifestyle, socioeconomic status, and family and school factors. Considering sleep onset latency as the outcome and 13 sleep-related factors as independent variables, we calculated the odds ratio using binary logistic regression. The longitudinal study was conducted with 1,703 boys and 1,919 girls whose sleep onset latency was within 30 min in Phase IV.

The following factors were found to be related to longer sleep onset latency in the short term: sleep duration, physical activity, game time, and self-esteem in boys and sleep duration, bedroom environment, game time, abdominal pain, long-standing illness, onset of puberty, mental health difficulties, and school avoidance feelings in girls. Regarding its long-term effects, having a single parent and self-esteem in boys and breakfast, game time, long-standing illness, obesity, onset of puberty, and school avoidance feelings in girls were associated with longer sleep onset latency.

Education of adolescent health and sleep hygiene at home and school should include both short-term and long-term associations between sleep and a healthy lifestyle by gender.