Subjective sleep quality in non-demented older adults with and without cognitive impairment

Sleep problems are prevalent among older adults who are at risk of developing dementia. Until now, there have been relatively few studies investigating subjective sleep quality in these individuals. The first objective of this study was to compare seniors with cognitive impairment no dementia (CIND) and older adults without cognitive impairment (non-CIND) on several subjective sleep measures. The second objective was to verify whether sleep parameters associated with CIND differ between men and women.

The population sample consisted of 2287 French-speaking older adults from Québec (Canada) aged between 65 and 96 years. Participants were classified as CIND or non-CIND on the basis of their mini mental state examination score using sex, age, and education-stratified normative data. All participants completed the Pittsburgh Sleep Quality Index, and responses of CIND and non-CIND individuals were compared. A series of confounding variables (age, education, chronic diseases, mood disorders, anxiety disorders, and use of psychotropic drugs) were statistically controlled for. Student's t-tests were performed to compare characteristics of CIND and non-CIND individuals; data from male and female participants were analyzed separately. Moreover, the association between each sleep variable and CIND was measured by odds ratios based on logistic regression.

On the whole, analyses revealed no significant association between subjective sleep parameters and CIND. Moreover, no difference was observed between men and women regarding subjective sleep quality.

Overall, these results suggest that subjective measures of sleep do not allow differentiating cognitively impaired older individuals from those with normal cognition.