Interaction between sleep timing and excessive daytime sleepiness in relation to metabolic syndrome among U.S. adults

Background The association between sleep timing and metabolic syndrome (MetS) and the interaction between sleep disorders and sleep timing in relation to MetS risk remain unclear. Methods Data from 14,138 participants from the 2015–2020 NHANES survey were analyzed. MetS was defined using the National Cholesterol Education Program-Adult Treatment Panel III criteria. Nocturnal sleep timing was categorized into early [18:00–22:00), normal [22:00–23:00), late [23:00–02:00), and very late [02:00–06:00). Sleep disorders included sleep disturbance, snoring, and excessive daytime sleepiness (EDS). Multivariate logistic regression and likelihood ratio tests were used to evaluate the association between sleep timing and MetS odds and its interactions with sleep disorders. Results After adjusting for confounding factors, very late sleep timing was associated with significantly higher MetS odds compared to normal sleep timing, with an odds ratio (OR) of 1.40 (95% confidence interval [CI]: 1.12–1.75). Among individuals without EDS, no significant associations were observed between sleep timing categories and the odds of MetS. However, both normal and very late sleep timing were significantly associated with higher odds of MetS among individuals with EDS. The ORs were 1.52 (95% CI: 1.06–2.18) and 3.04 (95% CI: 1.76–5.25), respectively. Significant interaction between sleep timing and EDS on MetS odds was observed (p interaction = 0.010). Conclusion Very late sleep timing was associated with higher odds of MetS. The association between sleep timing and MetS was significantly modified by EDS, highlighting the importance of addressing these sleep problems in MetS prevention strategies.