Comparative Analysis of Comprehensive HIV Knowledge and Risky Sexual Behavior among Unmarried Adolescent Girls and Young Women in Nigeria

Background Adolescent girls and young women (AGYW) aged 15–24 years suffer a considerable burden of HIV in sub-Saharan Africa, including Nigeria, where the prevalence in this age group is estimated at 1.3%. Hence, addressing the vulnerabilities inherent in this group is crucial in the fight against HIV. This study compared trends in comprehensive HIV knowledge and risky sexual behavior among unmarried AGYW in Nigeria over a decade. Methods We utilized secondary data from the Nigerian Demographic and Health Surveys (NDHS) conducted between 2008 and 2018. The outcome variable was risky sexual behaviour, measured as condom use during the most recent sexual encounter, which was analysed via binary regression to assess trends and associations with comprehensive HIV knowledge while adjusting for demographic and socioeconomic variables. Stata 16.1 was used for the analyses, with sample sizes ranging from 1,743 in 2008 to 1,714 in 2018. Results The study revealed that condom use among adolescent girls (15–19 years) increased from 32.0% in 2008 to 40.3% in 2013 but decreased to 36.7% in 2018. Among young women (20–24 years), condom use rose from 42.3% to 50.6% before declining to 41.0% in 2018. Comprehensive HIV knowledge among adolescent girls declined from 60.1% in 2008 to 50.3% in 2018, whereas it increased among young women, reaching 58.5% in 2018. Logistic regression revealed that comprehensive HIV knowledge significantly increased condom use among adolescent girls, with odds rising from 35% (OR: 1.35, p < 0.05) in 2008 to 72% (OR: 1.72, p < 0.05) in 2018, but its influence on young women declined over time. Conclusion AGYW in Nigeria face gaps in HIV knowledge and inconsistent condom use. Hence, there is a need for sustained, culturally sensitive HIV education and behavioural interventions. Strengthening collaborations between health services, schools and communities can empower AGYW, address regional disparities and reduce risky behaviours. Such integrated approaches are crucial for improving sexual health outcomes and reducing the incidence of HIV in AGYW.