Association Between Gastrointestinal and Sleep Problems in the General Population of Japan: A Cross-Sectional Community-Based Observational Study.

Background and aim Poor sleep is known to be associated with functional gastrointestinal (GI) problems in the general population, but the exact mechanisms underlying the relationship remain unclear. Deeper insights into the exact mechanisms underlying the connection may benefit individuals suffering from these conditions without efficient treatments. Therefore, this study investigated the association between functional GI symptom levels and sleep-related characteristics in the general population of Japan. Methods In this cross-sectional questionnaire-based observational study, data including the self-reported level of poor sleep and functional GI symptoms in the last one month were collected from consecutive individuals who visited a hospital in Miyagi Prefecture, Japan, for regular medical checkups between April 2020 and March 2023. The levels of other physical and mental conditions, such as stress at home, fatigability, irritability, thermoregulatory problems, and edema in the limbs, were measured with an 11-point Numerical Rating Scale (NRS) between 0 and 10. Additional sleep-related specific information, such as sleep length, wake-up time, bedtime, trouble falling asleep, and nocturnal awakening, were further collected. Correlations with functional GI symptoms in these characteristics were evaluated by bivariate correlation analyses and generalized regression analyses. Results A total of 151 consecutive adults aged ≥18 years (77 males and 74 females) participated in this study. In bivariate correlation analyses, chronic GI symptom levels were significantly correlated with stress at home (p=0.0005), fatigability (p=0.0008), irritability (p=0.0022), edema in the limbs (p<0.0001), and sleep problem (p<0.0001). In the following generalized regression analysis, significant correlations with GI symptom levels were observed in sleep problems (p=0.0042) and edema in the limbs (p=0.0256). Further bivariate correlation analyses using sleep-related subscales revealed that trouble falling asleep in bed (p=0.0001), midnight awakening (p=0.0143), and wakeup time (p=0.0465) were correlated with GI symptom levels. In the following generalized regression analysis, a significant correlation with GI symptom levels was observed in trouble falling asleep (p=0.0239). Conclusion Functional GI symptoms in the general population of Japan were associated with poor sleep, even after adjusting for daily stress and irritability levels. Among the sleep-related characteristics, trouble falling asleep was associated with GI dysfunctions. Assessing sleep-related information and achieving good sleep quality with smooth sleep induction may be a clue to relieving GI dysfunctions with uncertain causes.