Early adolescent pregnancy increases risk of incident HIV infection in the Eastern Cape, South Africa: a longitudinal study

• Type of Material: Article
• Authors: Nicola J. Christofides, University of Witwatersrand; Rachel K. Jewkes, University of Witwatersrand; Kristin Dunkle, Emory University; Mzikazi Nduna, University of Witwatersrand; Nwabisa Jama Jama Shai, University of Witwatersrand; Claire Sterk, Emory University
• Language: English
• Date: 2014-03-18
• Publisher: BioMed Central
• Publication Version: Final Published Version
• Copyright Statement: © 2014 Christofides NJ et al; licensee International AIDS Society
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.7448/IAS.17.1.18585
• Title of Journal or Parent Work: Journal of the International AIDS Society
• ISSN: 1758-2652
• Volume: 17
• Issue: 1
• Grant/Funding Information: This study was funded by the National Institute of Mental Health (grant numbers MH 64882-01, MH 64882-04S1A1 and 1R03MH085599) and the South African Medical Research Council.
• Keywords: HIV/AIDS; sexual risk behaviour; adolescent pregnancy; longitudinal data; South Africa
• Research Categories: Psychology, General; Health Sciences, Public Health

Abstract

Introduction Adolescents having unprotected heterosexual intercourse are at risk of HIV infection and unwanted pregnancy. However, there is little evidence to indicate whether pregnancy in early adolescence increases the risk of subsequent HIV infection. In this paper, we tested the hypothesis that adolescent pregnancy (aged 15 or younger) increases the risk of incident HIV infection in young South African women. Methods We assessed 1099 HIV-negative women, aged 15–26 years, who were volunteer participants in a cluster-randomized, controlled HIV prevention trial in the predominantly rural Eastern Cape province of South Africa. All of these young women had at least one additional HIV test over two years of follow-up. Outcomes were HIV incidence rates per 100 person years and HIV incidence rate ratios (IRRs) estimated by Poisson multivariate models. Three pregnancy categories were created for the Poisson model: early adolescent pregnancy (a first pregnancy at age 15 years or younger); later adolescent pregnancy (a first pregnancy at age 16 to 19 years); and women who did not report an adolescent pregnancy. Models were adjusted for study design, age, education, time since first sexual experience, socio-economic status, childhood trauma and herpes simplex virus type 2 infection. Results HIV incidence rates were 6.0 per 100 person years over two years of follow-up. The adjusted IRR was 3.02 (95% CI 1.50–6.09) for a pregnancy occurring at age 15 or younger. Women with pregnancies occurring between 16 and 19 years of age did not have a higher incidence of HIV (IRR 1.08; 95% CI 0.64–1.84). Early adolescent pregnancies were associated with higher partner numbers and a greater age difference with partners. Conclusions Early adolescent pregnancies increase the incidence of HIV among South African women. The higher risk is associated with sexual risk behaviours such as higher partner numbers and a greater age difference with partners rather than a biological explanation of hormonal changes during pregnancy.