Prevalence, associated factors, and limitations related to chronic back problems in adults and elderly in Brazil.

The objective was to analyze the epidemiological characteristics of chronic back problems in Brazil and study the association between their prevalence and demographic and socioeconomic factors, lifestyle, and health conditions. The study used micro-data from the Brazilian National Health Survey (PNS), 2013. The epidemiological indicators were: prevalence, time with chronic back problems, life cycle (from young adults to the elderly), limitations in activities of daily living, and mean age at onset of symptoms, according to sex and age bracket. In order to analyze inequality in chronic back problems according to socioeconomic characteristics and risk factors, a multivariate logistic regression model was used, based on life cycle stages, with the presence of chronic back problems as the dependent variable and the following independent variables: sex, schooling, area of residence, race/color, self-rated health, types of chronic diseases, body mass index (BMI), and physical activity. Prevalence of chronic back problems in Brazil was 18.5%, and was higher in women than in men (21.1%; 95%CI: 20.2-21.9). Mean age at onset of chronic back problems was 35 years. There was an association between chronic back problems and lower schooling, poor self-rated health, and presence of the majority of the selected chronic diseases. Area of residence, BMI, age, and race/color were weakly associated or not associated with chronic back problems. Prevalence of chronic back problems stabilized at 50 years of age, but the severity of limitations increased at older ages. As in other countries, high prevalence and the impact on living conditions revealed the need for epidemiological studies on chronic back problems in Brazil. The results suggest that health promotion and the prevention of chronic back problems should be intensified, especially before 50 years of age, considering the on-going population aging in Brazil.