Time trends and inequalities in interpersonal violence during adolescence: a comparison of three birth cohort studies in Brazil over twenty years, 2000-2020

Abstract Purpose: The aim of this study is to examine trends and inequalities in interpersonal violence among adolescents. Methods: Three population-based birth cohorts were conducted, including all births in Pelotas city in a calendar year (1982, 1993, 2004), with over 4200 births in each cohort. Corporal punishment by parents and involvement in physical fights were assessed through self-reported confidential questionnaires when participants were 11, 15 and 18 years of age. The prevalence of violence outcomes was estimated, stratifying by sex and family income group for each cohort, and income-related inequalities were assessed through time. Results: We found significant reductions in corporal punishment by parents between cohorts, both at ages 11 (PR:0.83) and 15 years (PR:0.70). There were also reductions in income-related inequalities in corporal punishment, mainly for boys. Considering physical fights, while there was a reduction in prevalence at age 18 years for girls (PR:0.50), there was an increase for boys at age 11 years (PR:1.22). There was no change in the prevalence of fighting at age 15 for either sex. Income-related inequalities reduced regarding involvement in fights at age 18 for girls, but they remained significant at earlier ages - with a higher prevalence of fights among the poorest adolescent girls in comparison to the richest. Conclusions: Despite encouraging declines in corporal punishment over the past two decades, trends in physical fights are of concern, particularly for boys. Continued monitoring is vital to support effective violence prevention policies.