**Background:** Cardiovascular disease (CVD) is the leading cause of death globally, with nearly 80% of CVD deaths occurring in low- and middle-income countries. Slum populations—nearly one billion people worldwide—face social and environmental conditions that may increase CVD risk, yet they are infrequently studied. Brazil has over 16% of its urban population living in slums (favelas) and is characterized by extreme wealth inequality. This study aimed to assess socioeconomic inequalities in CVD risk factors comparing slum and non-slum populations in Brazil.
**Methods:** This was a cross-sectional analysis of the 2019 Brazilian National Health Survey (Pesquisa Nacional de Saúde, PNS), a country-wide household-based survey conducted by the Brazilian Institute of Geography and Statistics (IBGE) and the Ministry of Health. A total of 94,114 individuals who answered the individual questionnaires were included. The UN-Habitat definition of slums was used, identifying slum residents as those lacking access to improved water, improved sanitation, sufficient living area, or housing durability. Eleven binary outcomes were analyzed: six behavioral risk factors (low vegetable consumption [<5 days/week], low fruit consumption [<5 days/week], high red meat consumption [≥3 days/week], current smoking, heavy alcohol consumption [≥4 drinks/day], low physical activity [<150 minutes/week]), four metabolic risk factors (overweight [BMI >25 kg/m²], doctor-diagnosed hypertension, diabetes, high cholesterol), and doctor-diagnosed CVD (heart disease or stroke). Adjusted Poisson regression models were used, controlling for location of residence, sex, age, race/ethnicity, education, employment, and household income per capita. All analyses accounted for clustered sampling and were weighted for non-response.
**Key Results:** According to the UN-Habitat definition, 14.4% (95%CI 13.7–15.0) of the Brazilian population were slum residents. Compared to urban non-slum inhabitants, slum inhabitants had significantly higher prevalence of: low vegetable consumption (APR: 1.083, 95%CI 1.048–1.119); low fruit consumption (APR: 1.037, 95%CI 1.010–1.065); heavy alcohol consumption (APR: 1.045, 95%CI 1.028–1.062); and physical inactivity (APR: 1.025, 95%CI 1.007–1.044). Slum residents had lower prevalence of smoking (APR: 0.920, 95%CI 0.847–0.999) and high red meat consumption (APR: 0.962, 95%CI 0.934–0.990). There were no statistically significant differences between slum and urban non-slum populations in doctor-diagnosed metabolic risk factors or CVD: overweight (APR: 0.992, 95%CI 0.966–1.019), hypertension (APR: 0.987, 95%CI 0.941–1.034), diabetes (APR: 1.030, 95%CI 0.942–1.127), high cholesterol (APR: 1.044, 95%CI 0.969–1.125), and CVD (APR: 1.006, 95%CI 0.891–1.136). Rural populations had significantly lower prevalence of all metabolic risk factors and CVD compared to urban non-slum populations. Strong socioeconomic gradients were observed: individuals with higher education and income had lower prevalence of behavioral risk factors; non-White populations (Black and Pardo/mixed) had higher prevalence of low fruit/vegetable consumption, heavy alcohol use, and hypertension; and women had higher prevalence of heavy alcohol consumption (APR: 1.046, 95%CI 1.032–1.061) and physical inactivity (APR: 1.079, 95%CI 1.062–1.096) but lower smoking and healthier diets.
**Clinical Implications:** Slum environments in Brazil are associated with higher rates of behavioral CVD risk factors that are not fully explained by individual socioeconomic characteristics, suggesting that local environmental factors—such as poor food availability, unsafe neighborhoods limiting physical activity, and stress from poor housing—may drive these disparities. The lack of difference in diagnosed metabolic risk factors between slum and non-slum urban populations may reflect under-diagnosis in slum populations due to barriers in healthcare access. These findings highlight the need for targeted public health interventions in slums, such as supervised physical activity programs (e.g., the Carioca Academy Program in Rio de Janeiro) and improved nutrition programs (e.g., the National School Meal Programme). Addressing socioeconomic inequalities—by education, income, and race—remains a priority for reducing CVD risk in Brazil.