Age-disparate relationships and HIV incidence in adolescent girls and young women: evidence from Zimbabwe.

Robin Schaefer,Simon Gregson,Owen Mugurungi,Albert Takaruza,Jeffrey W Eaton,Constance Nyamukapa,Rufurwokuda Maswera,Rebecca Rhead

doi:10.1097/qad.0000000000001506

Abstract

Age-disparate sexual relationships with older men may drive high rates of HIV acquisition in young women in sub-Saharan Africa, but evidence is limited. We investigate the association between age-disparate relationships and HIV incidence in Manicaland, Zimbabwe. A general-population open-cohort study (six surveys) (1998-2013). A total of 3746 young women aged 15-24 years participated in consecutive surveys and were HIV-negative at the beginning of intersurvey periods. Last sexual partner age difference and age-disparate relationships [intergenerational (≥10 years age difference) and intragenerational (5-9 years) versus age-homogeneous (0-4 years)] were tested for associations with HIV incidence in Cox regressions. A proximate determinants framework was used to explore factors possibly explaining variations in the contribution of age-disparate relationships to HIV incidence between populations and over time. About 126 HIV infections occurred over 8777 person-years (1.43 per 100 person-years; 95% confidence interval = 1.17-1.68). Sixty-five percent of women reported partner age differences of at least 5 years. Increasing partner age differences were associated with higher HIV incidence [adjusted hazard ratio (aHR) = 1.05 (1.01-1.09)]. Intergenerational relationships tended to increase HIV incidence [aHR = 1.78 (0.96-3.29)] but not intragenerational relationships [aHR = 0.91 (0.47-1.76)]. Secondary education was associated with reductions in intergenerational relationships [adjusted odds ratio (aOR) = 0.49 (0.36-0.68)]. Intergenerational relationships were associated with partners having concurrent relationships [aOR = 2.59 (1.81-3.70)], which tended to increase HIV incidence [aHR = 1.74 (0.96-3.17)]. Associations between age disparity and HIV incidence did not change over time. Sexual relationships with older men expose young women to increased risk of HIV acquisition in Manicaland, which did not change over time, even with introduction of antiretroviral therapy.

Highlights

HIV infection rates remain extremely high in adolescent girls and young women in many populations in subSaharan Africa
As HIV prevalence is higher among older men than in younger men [3], young women engaging in sexual relations with older men can be at a greater risk of contracting HIV compared with those forming relationships with aged men
A total of 126 new HIV infections occurred over 8777 person-years (1.43 per 100 personyears, 95% confidence intervals (CIs) 1⁄4 1.17–1.68)

Summary

Introduction

In South Africa and Zimbabwe, for example, HIV incidence in women aged 15–24 years is four times higher and twice as high, respectively, as in men of the same age [1,2]. These high infection rates present huge challenges for the health and wellbeing of these women and for the affordability and sustainability of national antiretroviral treatment (ART) programmes. Mathematical modelling studies show that sexual relationships with older men (age-disparate relationships) can be a major driver of HIV infection in young women [4]. Age-disparate sexual relationships are often characterized by socioeconomic asymmetries, which can leave young women unable to negotiate condom use or vulnerable to forced sex [5,6]

Methods

Results

Discussion

Conclusion