Sex Difference in the Association of Sleep Disturbances with Cognitive Function Impairment in Elderly

Objectives: To examine the prevalence of sleep disturbances and cognitive impairment in elderly people according to gender, and to determine the association of sleep with cognitive impairment according to sex.

Methods: This was a cross-sectional study derived from the 2009 population-based Taiwan National Health Interview Survey. A total of 2413 elderly (ages of 65 years or older) with 1094 males and 1319 female were included. The cognitive impairment as well as subjective sleep characteristics including sleep hours, difficulty in initiating sleep, difficulty in maintaining sleep, early morning awakening, daytime sleepiness, difficulty in breathing during sleep, and daytime naps were assessed by survey questions.

Results: The prevalence of cognitive function impairment was 16.3% in male and 27.1 % in female elderly people. Both male and female elderly people with cognitive function impairment had higher prevalence rates of sleep disturbances in elderly adults than those without cognitive function impairment. In male elderly people, difficulty in breathing during sleep and prolonged sleep duration (> 8.5 h) were significantly associated with cognitive function impairment (adjusted odds ratio = 2.43 and 2.06, 95% confidence intervals =1.48-3.98 and 1.19-3.60, respectively) after adjusted for potential confounders. In female elderly people, only prolonged sleep duration (>8.5h) had higher likelihoods of cognitive function impairment (adjusted odds ratio = 2.35, 95% confidence interval =1.36-4.07) controlling for confounders.

Conclusions: This population-based study confirms that gender-specific association between sleep disturbances and cognitive function impairment in elderly people, warranting further investigation of the underlying causes.