[Loneliness and its association with sociodemographic and health indicators in Brazilian adults and older adults: ELSI-Brazil].

This study aimed to investigate the prevalence of loneliness and its associations with sociodemographic and health indicators in a nationally representative sample of Brazilian adults and older adults. Data from the baseline (2015-2016) of the Brazilian Longitudinal Study of Aging (ELSI-Brazil) were analyzed, and participants with complete information on the variables of interest (n = 7,957) were included. Loneliness was the outcome variable, which was based on the question "How often do you feel alone or lonely: always, sometimes, or never?" Independent variables included sociodemographic indicators and health behaviors and conditions. The analyses included the Pearson's chi-square test for calculating relative frequencies, and Poisson regression for estimating prevalence ratios (PR) and their respective 95% confidence intervals (95%CI). The prevalence of always feeling lonely was 16.8%; sometimes, 31.7%; and never, 51.5%. Significant associations were observed between always feeling lonely and depression (PR = 4.49; 95%CI: 3.93-5.11), living alone (PR = 2.44; 95%CI: 2.12-2.82), low education level (PR = 1.93; 95%CI: 1.61-2.32), being a woman (PR = 1.53; 95%CI: 1.36-1.72), self-rated poor/very poor health (PR = 1.48; 95%CI: 1.27-1.73), and poor/very poor sleep quality (PR = 1.21; 95%CI: 1.05-1.41). Given its potential to harm quality of life, it is necessary to longitudinally understand the trajectories of loneliness and associated variables, and to use this knowledge to design public policies and health interventions that could benefit the biopsychosocial well-being of Brazilian adults and older adults.