Sleep complaints and metabolic syndrome in an elderly population: the Three-City Study

Objectives: To assess whether sleep complaints (rather than clinically defined sleep disturbances) were associated with the metabolic syndrome (MetS) and each of its components in an elderly population.

Methods: Cross-sectional analyses of data from the French Three City Study, a large multicenter cohort of elderly community-dwellers.

Participants: 6,354 participants (56.4% women, median age 73; range: 65-97 years).

Measurements: Frequency of insomnia complaints (difficulty in initiating sleep, difficulty in maintaining sleep [DMS], and early morning awakening) and excessive daytime sleepiness (EDS) were self-reported. MetS was assessed using National Cholesterol Education program Adult Treatment Panel III criteria.

Results: A total of 977 participants had MetS. After adjustment for a large range of potential confounders, we report an association between the number of insomnia complaints and MetS. Among insomnia complaints only DMS was consistently associated with MetS (OR: 1.23, 95% CI: 1.06 to 1.43). Our results showed that EDS independently increased the risk of MetS (OR: 1.46, 95% CI: 1.18 to 1.81 for "frequently"; OR: 1.99, 95% CI: 1.49 to 1.67 for "often"). The EDS-MetS association was independent of past-history of cardiovascular disease, insomnia complaints, and obesity and loud snoring.

Conclusion: We report significant independent associations between frequent sleep complaints (EDS and to a lesser extent DMS) and MetS in the elderly with potential implications in terms of management and cardiovascular prevention in general geriatric practice. Prospective studies are required to clarify the direction of the association between sleep complaints and MetS.