Insomnia symptoms and related factors in a community-based population: The Yamagata Cohort study

Insomnia is prevalent and is a risk factor for the development of lifestyle-related diseases and early death. To improve insomnia, it is necessary to identify the factors that affect it. This study investigated the associations between insomnia symptoms and mental, physical, and environmental factors in the general Japanese population.

The study participants were 7,873 individuals who responded to the Health and Lifestyle Survey questionnaire that included sleep-related items between December 2021 and March 2022. Insomnia symptoms were defined as a score of 6 or higher on the Athens Insomnia Scale (AIS). A multivariate logistic regression analysis was performed to identify factors independently associated with insomnia symptoms.

Of all subjects, 23.4% had insomnia symptoms. Factors associated with insomnia symptoms were older age, female sex, very difficult living conditions on current income, pain/discomfort, anxiety, lack of happiness, frequent nocturia, long duration from bathing time to bedtime, bedroom lighting, and short walking duration. The subgroup analysis showed stronger associations between walking time in men, higher body mass index in women, time from bathing time to bedtime, and daily walking duration in older adults.

Insomnia symptoms were common in community-based populations and were independently associated with three different factor groups including physical, psychological, and environmental factors. Improvements in insomnia symptoms require appropriate practical support tailored to an individual's situation.