The association between multiple sleep-related characteristics and the metabolic syndrome in the general population: the New Hoorn study

Background: Previous studies have investigated the association between sleep duration, insomnia, day-time napping and metabolic syndrome individually, but never conjointly. In addition, the association with sleep medication use has yet to be investigated. We aimed to examine the associations between these sleep-related characteristics and the metabolic syndrome, individually and conjointly, in a population-based cohort. Material and methods: We used cross-sectional data of 1679 participants from the New Hoorn study, 52.6% women and age 60.8 + 6.4y. Sleep duration, insomnia, and day-time napping were measured using validated questionnaires. The use of sleep medication was documented by the registration of dispensing labels. The metabolic syndrome was defined according to ATP III. Linear and Poisson regressions were used, and all analyses were adjusted for age, sex, education level, job status, smoking, physical activity, depression and BMI. Results: In our population-based cohort, 447 (26.6%) persons had the metabolic syndrome. Individual associations showed that, after correction, day-time napping for ≤30 min and >30 min was associated with a prevalence ratio for the metabolic syndrome of 1.28 (95% CI: 1.1–1.5) and 1.74 (95% CI: 1.4–2.2), respectively, compared to participants who did not nap. Sleep duration, insomnia, and sleep medication use were not associated with the metabolic syndrome individually. However, conjointly analyses showed that, after correction, having ≥2 sleep-related characteristics was associated with a PR of 1.36 (95% CI: 1.0–1.8) of having the metabolic syndrome, compared to having no sleep-related characteristics. Conclusion: Sleep-related characteristics were associated with a higher prevalence of the metabolic syndrome in the general population.