Associations of sleep duration variability and depressive symptoms with gastrointestinal disease among middle-aged and older adults

The relationship between variability in sleep duration and gastrointestinal disorders remains insufficiently explored. This study aimed to examine this connection and evaluate the potential mediating influence of depressive symptoms on this association. This research utilized data were obtained from the China Health and Retirement Longitudinal Study (CHARLS) and Health and Retirement Study (HRS). The association between gastrointestinal diseases and changes in sleep duration was explored using quartile grouping, restricted cubic spline curves, subgroup analyses, and sensitivity analyses. The mediating effect of depressive symptoms was evaluated by using a mediation effect model. A total of 5570 participants from CHARLS and 2539 from HRS were included, of which 490 (8.80%) and 274 (10.79%), respectively, developed gastrointestinal disease. Greater sleep duration variability was linked to an increased risk of gastrointestinal disease, particularly among participants in the highest quartile (CHARLS: odds ratio = 1.43; HRS: odds ratio = 1.84). Restricted cubic spline analyses showed that, as sleep variability increased, the risk of gastrointestinal disease also increased in a linear manner, and depression was found to partially mediate this association by influencing the pathway between sleep variability and disease risk. This study finds that changes in sleep duration were linked to gastrointestinal diseases, with depression playing a mediating role. This suggests that changes in sleep duration and mental health may help to prevent gastrointestinal disturbances.