Secondhand smoke exposure at home in Brazilian capital cities: time trends from 2009 to 2023

Exposure to tobacco smoke, including secondhand smoke, has been linked to adverse health outcomes, particularly an increased risk of non-communicable diseases. To analyze time trends in the prevalence of secondhand smoke exposure at home in Brazilian capital cities from 2009 to 2023. Time series study using data from the Surveillance of Risk and Protective Factors for Chronic Diseases by Telephone Survey. The following variables were analyzed: Secondhand smoke (SHS) exposure at home, according to sex, education, age, and Brazilian capitals. Time trends were analyzed using Joinpoint regression models, and the Average Annual Percent Change (AAPC) and respective 95% confidence intervals (95%CI) were estimated. The prevalence of secondhand smoke exposure at home showed a downward trend, decreasing from 12.7% in 2009 to 6.4% in 2023. This trend was observed in the overall population and across all sex, education, and age groups, with the highest prevalence among women (13.4% in 2009 to 6.6% in 2023) and individuals aged 18–24 years (19.6% in 2009 to 9.9% in 2023). The Brazilian capitals, there was a trend towards stability in Brasília (AAPC − 0.4, 95%CI -3.3; 1.4). Segments with stable trends were observed in the 45–54 years age group and in the cities of Boa Vista, Campo Grande, Natal, Palmas, Rio de Janeiro, São Luís, and Brasília. The prevalence of secondhand smoke exposure at home declined; however, stable trends were observed in some age groups and Brazilian capital cities. These findings highlight the importance of tobacco control policies and reinforce the need to strengthen tobacco control efforts and increase awareness of the harms of secondhand smoke exposure at home.