Poor sleep quality is an important modifiable risk factor for dementia: Population attributable fraction of poor sleep in a Brazilian population-based study

Objectives

The populational impact of poor sleep quality and the risk of dementia is unclear. We analyzed the Population Attributable Fraction (PAF) of poor sleep quality for dementia, and its association with other two sleep parameters through self-reported and single questions collected in a large-scale Brazilian cohort (ELSI-Brazil).

Methods

A subset of the ELSI-Brazil with complete responses to sleep quality was retrieved for this study. This is a large representative sample of the Brazilian elderly population with an extensive assessment of sociodemographic and health risk variables. Prevalence of poor sleep quality was estimated according to the complex sample design, and its PAF was measured using a meta-analytic relative risk. A total of 6024 (56.3% women, mean 62.8 ± 9.5 years of age) individuals had complete responses.

Results

The prevalence of poor sleep quality was 24.9% (95%CI 23%–26%), and the PAF of poor sleep quality including other 10 modifiable risk factors of dementia was 52.5% in Brazil. Secondary analyses identified that sleep quality, restorative sleep and sleep drug usage varied considerably according to age ranges, race, and gender.

Conclusions

Poor sleep quality is an important populational modifiable risk factor for dementia in Brazil. Targeted interventions may provide an important impact in preventing dementia in low- and middle-income countries.