Insomnia in older adult females is highly associated with metabolic syndrome

Purpose: The aim of this study is to investigate the relationships between insomnia and metabolic syndrome among Taiwanese older adults. Methods: This cross-sectional study enrolled participants aged over 60 years from outpatient clinics between July and September 2018. Demographic characteristics of all participants and questionnaire data for sleep duration, use of hypnotic agents, baseline activities of daily living, 5 items of the geriatric depression scale, comorbidities, medications, and risk of obstructive sleep apnea were obtained. Insomnia was defined by scores of questionnaires of the Chinese version of the Athens Insomnia Scale higher or equal to 6 points. Metabolic syndrome was diagnosed according to criteria of the National Cholesterol Education Program Adult Treatment Panel III. Multivariable forward stepwise logistic regression analysis was applied to investigate independent associations between insomnia and metabolic syndrome before and after stratifying by gender. Results: Among the 336 participants (mean age 74.9 ± 8.5 years, female 49.1%), 63.1% participants had metabolic syndrome, with significantly higher prevalence among females than males (males 56.7%; females 69.7%). Participants with metabolic syndrome had higher rates of insomnia (34.0% vs. 21.8%, P = 0.018). The significant associations between insomnia and metabolic syndrome disappeared after adjusting for all covariates. However, insomnia was independently associated with metabolic syndrome in older females (adjusted OR 2.614, 95% CI 1.011–6.763, P = 0.048) after adjusting for all covariates. Conclusions: Insomnia is significantly associated with metabolic syndrome among older female adults. These findings suggest that gender may play a role in the pathogenesis of insomnia and metabolic syndrome in older adults.