Abstract
OBJECTIVE: to analyze prevalence of sexual initiation and associated factors in adolescents in Piauí. METHODS: this was a cross-sectional study, with secondary data from the 2015 National Adolescent School-based Health Survey. Hierarchical analysis was performed using robust Poisson regression. RESULTS: a total of 3.872 adolescents were interviewed. Prevalence of sexual initiation was 24.2%; risk factors for sexual initiation were being male [prevalence ratio (PR) = 2.18; 95% confidence interval (95%CI) 1.90;2.47], being 15 years old or over (PR = 2.49; 95%CI 2.18;2.76), living with mother (PR = 0.68; 95%CI 0.54;0.82), working (PR = 1.82; 95%CI 1.55;2.10), attending a public school (PR = 1.39; 95%CI 1.09;1.75), practicing bullying (PR = 1.50; 95%CI 1.31;1.72), using alcohol (PR = 2.35; 95%CI 2.09;2.64), using cigarettes (PR = 1.46; 95%CI 1.22;1.70) and using illicit drugs (PR = 1.40; 95%CI 1.15;1.66). CONCLUSION: prevalence of sexual initiation was high and associated with sociodemographic characteristics and vulnerable health behaviors, indicating the need for health promotion strategies.