Seasonal Variation, Circadian Patterns, and Night Eating Syndrome Among Older Adults: The Mediating Role of Sleep Quality

Abstract

Objective: We aimed to examine whether sleep quality mediates the relationship between seasonal variation, circadian pattern, and night eating syndrome in community-dwelling older adults. Methods: A cross-sectional study was conducted with 336 community-dwelling older adults (aged ≥ 60 years) recruited from geriatric social clubs. Participants completed validated instruments, including the Global Seasonality Scale (GSS), Morningness–Eveningness Questionnaire (MEQ), Night Eating Diagnostic Questionnaire (NEDQ), and Pittsburgh Sleep Quality Index (PSQI). Path analysis with bootstrapping (5000 resamples) was used to estimate direct and indirect associations among the study variables. Results: The mean age was 66.8 ± 5.9 years (56.8% male). Moderate to severe seasonal variation was observed in 68.2% of participants, while 85.1% reported poor sleep quality. Morning circadian pattern predominated (56.9%), and 23.2% met criteria for full night eating syndrome. Path analysis identified a significant indirect association between seasonal variation and circadian pattern through sleep quality (B = −0.038, 95% CI [−0.051, −0.026]), corresponding to 41% of the total modeled association. Similarly, a significant indirect association between seasonal variation and night eating syndrome through sleep quality was observed (B = 0.053, 95% CI [0.037, 0.068]), corresponding to 37% of the total modeled association. All direct and indirect paths were statistically significant (p < 0.001). Conclusions: Sleep quality was significantly involved in the observed relationships between seasonal variation, circadian pattern, and night eating syndrome among older adults, with the path models indicating both direct and indirect associations. These findings emphasize the interconnected nature of seasonal sensitivity, sleep characteristics, circadian preference, and nighttime eating behavior in later life. Further longitudinal research with repeated seasonal assessments is warranted to clarify the temporal relationships among these factors and to determine the potential value of sleep-focused preventive and clinical approaches.