Assessing Multilevel Determinants of HIV Acquisition among Adolescent Girls and Young Women in Sub-Saharan Africa

Abstract

Adolescent girls and young women (AGYW) aged 15 to 24 in sub-Saharan Africa (SSA) face disproportionate HIV risk, accounting for 83% of global HIV cases among AGYW. However, existing research has predominantly focused on individual-level biomedical and behavioral determinants, with less attention given to the multilevel social and structural contexts shaped by gender inequality that influence HIV acquisition. This dissertation adopts an epidemiological and gender-sensitive approach to examine multilevel determinants, including both risk and protective factors, of HIV acquisition among AGYW in SSA.This dissertation developed the INFORM-HERS framework (INtegrated Framework fOR assessing Multilevel determinants of HIV acquisition affecting adolescent girls and young women in Sub-Saharan Africa: Assessing Risk and pRotective factors) using the "Up and Down" theory integration method to synthesize three established frameworks: the Modified Social Ecological Model, the Theory of Gender and Power, and the Center for Latino Adolescent and Family Health Framework of Social Determinants of Health Mechanisms. INFORM-HERS incorporates gender inequality risk factors, social protective factors, and AGYW-specific developmental transitions, organizing determinants across individual, social, and structural levels to provide a theoretical foundation for multilevel interventions in SSA. Guided by the INFORM-HERS framework, structural determinants of HIV acquisition were theoretically defined, operationalized, and measured at the community level using data from the Botswana Combination Prevention Project (BCPP), a community-randomized HIV prevention trial that enrolled 3,413 adolescents and young adults aged 16 to 24 across 30 communities. Four structural determinants were computed: gender-based income inequality, gender-based education inequality, male HIV viral detectability, and AGYW community engagement. Adaptations from the United Nations Development Programme Gender Inequality Index were used to operationalize gender inequalities in income and education between AGYW and adolescent boys and young men (ABYM), with higher inequality ratios indicating greater disparities disadvantaging AGYW relative to ABYM in the community. Heterogeneity of these community-level measures was assessed using the I² statistic and Q-test, revealing substantial variation across communities, particularly for AGYW community engagement (I² = 84.14%, p < .0001), income inequality (I² = 73.37%, p < .0001), and education inequality (I² = 55.58%, p = .0001). Spearman correlation analyses demonstrated moderate positive associations between community-level income and education inequality and community-level HIV incidence among AGYW, providing empirical support for the feasibility and relevance of leveraging community-randomized trial data to measure structural HIV determinants. Multilevel hierarchical survival models, with individuals nested within communities, were then used to examine the effect of these multilevel determinants on the monthly risk of HIV acquisition among 1,672 AGYW aged 16 to 24 across the 30 BCPP communities. Among 55 seroconversions across 45,327 person-months of follow-up, findings demonstrated that each unit increase in community-level education inequality increased AGYW's HIV acquisition risk by 23% (adjusted hazard ratio [aHR] = 1.23; 95% CI: 1.04–1.46; p = 0.015). At the individual level, lack of post-secondary education increased risk approximately 8-fold (aHR = 7.57; 95% CI: 1.73–33.19; p < 0.01), and partner concurrency doubled risk (aHR = 2.05; 95% CI: 1.04–4.04; p = 0.039), while poverty-level income unexpectedly showed a protective effect (aHR = 0.34; 95% CI: 0.17–0.71; p < 0.01). These findings provide evidence that HIV acquisition determinants operate simultaneously across individual and structural levels, underscoring the need for multilevel, gender-sensitive prevention strategies and informing future HIV prevention programs for AGYW in SSA.