Sleep quality and associated factors in adults living in the southern Brazil: A population-based study.

Objective: To analyze sleep quality and associated socio-demographic and lifestyle factors in participants from a city originally colonised by Germans in southern Brazil.

Methods: A cross-sectional population-based study of 2333 individuals aged 20 to 79 years. Data was collected by interview using a structured questionnaire. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. The prevalence of poor sleep quality (PSQI score five or more) was estimated and the associations with study variables were measured by crude and adjusted prevalence ratios using Poisson regression.

Results: participants were mostly women (50.9 %), with an average age of 43.3 years. The median total PSQI score was 4 (IQ = 3-7). The frequency of poor sleep quality was 32.7 % (95 % CI 30.7-34.4), higher in older adults (44.0 % vs 30.7 %; p<0.001) and women (40.0 % vs 25.2 %; p<0.001). Multivariate analysis showed that women (PR = 1.3; 95%CI 1.1- 1.5; p<0.001), former smokers (PR = 1.2; 95%CI 1.0-1.4; p = 0.014), current smokers (PR = 1.3; 95%CI 1.1-1.5; p = 0.006), depression (PR = 1.5; 95%CI 1.3-1.7; p<0.001), taking 5 or more medications (PR = 1.2; 95%CI 1.1-1.4; p = 0.001), self-perceived fair health (PR = 2.1; 95%CI 1.8-2.4; p<0.001) or poor/very poor health (PR = 2.6; 95%CI 2.1-3.1; p<0.001) were risk factors for poor sleep quality. Germanic culture (PR = 0.8; 95%CI 0.7-0.9; p<0.001), high school (PR = 0.8; 95%CI 0.6-1.0; p = 0.046) or elementary school (PR = 0.7; 95%CI 0.6-1.0; p = 0.025) or being at work (RP = 0.8; 95%CI 0.7-0.9; p = 0.002) were inversely associated with poor sleep quality.

Conclusions: Women, older adults and some clinical, social, cultural and behavioural conditions are associated with poor sleep quality.