Sleep problems and underweight among adolescent girls and adult women aged 12-49 years: A cross-sectional, web-based survey in Japan

OBJECTIVES: Underweight is a common health concern among individuals of reproductive age. Although sleep and metabolic regulation share neuroendocrine pathways, the relationship between underweight and sleep problems remains unclear. This study aimed to investigate the associations between underweight and questionnaire-based sleep-related outcomes among adolescent girls and adult women. METHODS: These cross-sectional, web-based surveys were conducted from November to December 2023 among adolescent girls (aged 12-18 years) and adult women aged 18 to 49 years. Valid responses were obtained from 996 adolescent girls and 4689 adult women. Logistic regression analyses were conducted within age-defined subgroups to examine associations between weight categories and sleep-related outcomes, including a sleep debt-related pattern with daytime sleepiness and self-reported insomnia symptoms, adjusting for sociodemographic and lifestyle factors. RESULTS: Among respondents, 14.7% of adolescent girls and 23.5% of adult women were underweight. Underweight was not associated with either of the sleep-related outcomes among adolescent girls. In adult women, underweight was associated with self-reported insomnia symptoms in women in their 20s, with no associations observed in other age groups. An interaction between age and underweight was observed, suggesting that this association weakened with increasing age. CONCLUSIONS: Underweight was associated with self-reported insomnia symptoms, but not with a sleep debt-related pattern with daytime sleepiness, among adult women in their 20s. These findings suggest that sleep assessment may be considered as part of comprehensive strategies addressing underweight, although further studies using validated sleep measures are needed.