Sexual Initiation Before Age 14 and Co-Occurrence of Health Risk Behaviors Among Brazilian Adolescents: Data from the National School Health Survey 2015

Introduction Sexual initiation before age 14 is associated with risky sexual behaviors, substance use (alcohol, tobacco, and illicit drugs), mental disorders, body dissatisfaction, and behaviors indicative of eating disorders. However, there is not enough evidence in Brazil about the association between early sexual initiation and co-occurrence of health risk behaviors. This study examined whether early sexual initiation is associated with the co-occurrence of health risk behaviors among Brazilian adolescents. Methods Cross-sectional study using data from the 2015 National School Health Survey, with a representative sample of 3096 high school students from public and private schools in Brazil. The exposure was the sexual initiation before 14, referred to as Early Sexual Initiation (ESI). The outcomes were four health risk-behaviors domains: risky sexual behavior, substance use, internalizing symptoms, and unhealthy weight control behavior. We used Venn diagrams to describe the co-occurrence of risk behaviors. Multiple Poisson regression was performed.stratified by sex and adjusted for covariates. Results Co-occurrence of health risk behaviors was greater among adolescents with ESI, and it was more prevalent among girls (11.3% early vs 6.9% not early) than boys (5.8% early vs 4.1% not early). ESI was associated with no condom use in first intercourse (PR boys : 1.81, 95% CI = 1.56–2.10; PR girls : 1.40, 95% CI = 1.06–1.83) and in last intercourse (PR boys : 1.29, 95% CI = 1.06–1.57; PR girls : 1.58, 95% CI = 1.31–1.90), having four or more sex partner during their life (PR girls : 2.65, 95% CI = 2.03–3.46; PR boys : 1.59, 95% CI = 1.40–1.80) and unhealthy weight control practices to lose weight (PR boys : 1.76, 95% CI = 1.21–2.57; PR girls : 1.80, 95% CI = 1.11–2.92). ESI was associated with alcohol, tobacco and illicit drug use among girls (PR alcohol : 1.21, 95% CI = 1.02–1.44; PR tobacco : 1.74, 95% CI = 1.10–2.77; PR illicit drugs : 1.83, 95% CI = 1.07–3.12), and with alcohol (PR alcohol : 1.22, 95% CI = 1.08–1.38) and illicit drug use (PR illicit drugs : 1.43, 95% CI = 1.02–2.00) among boys. Conclusion Adolescents with ESI were more vulnerable to the co-occurrence of several health risk behavior. Girls with ESI were more vulnerable to this co-occurrence, although vulnerability among boys cannot be ignored. Policy Implications Understanding this co-occurrence can contribute to the legislature and education and health sectors elaborating sex