Abstract
OBJECTIVES: The aim of this study was to test the association of current contextual income inequality, contextual income inequality experienced during childhood, and individual factors with oral-health-related quality of life (OHRQoL) in adolescents. METHODS: Individual data of 3,854 adolescents aged 15-19 years from the Brazilian Oral Health Survey (SB Brasil Project) nested within 27 cities and contextual income inequality were analysed. OHRQoL was assessed using the Oral Impacts on Daily Performance (OIDP) questionnaire. The individual variables were demographic characteristics, socio-economic factors, and oral clinical measures. The Gini Index was used to evaluate city-level income inequality in 2003 (during childhood) and in 2010 (current) according to the tertiles of distribution. Multi-level Poisson regression was used to test the association of contextual income inequality and individual characteristics with OIDP extent according to the WHO framework on social determinants of health. RESULTS: The prevalence of OIDP was 34.5%. In the adjusted analysis, adolescents living in the cities with high-level income inequality during childhood were 1.75 times more likely (95% confidence interval 1.23-2.48) to have a higher mean of OIDP extent. Current income inequality was not associated with OIDP extent in adolescents. CONCLUSIONS: Contextual income inequality during childhood was a structural determinant of OHRQoL among Brazilian adolescents after adjustment for individual demographic characteristics, socio-economic factors and oral clinical measures. Reducing social inequalities through inter-sectoral actions should be on the political agenda to improve adolescents' oral health.