title: Oral and injectable contraceptive use and HIV acquisition risk among women in four African countries: a secondary analysis of data from a microbicide trial.
abstract: OBJECTIVE
  To assess the effect of oral and injectable contraceptive use compared to nonhormonal contraceptive use on HIV acquisition among Southern African women enrolled in a microbicide trial.
  
  
  METHODS
  This is a prospective cohort study using data from women enrolled in HIV Prevention Trials Network protocol 035. At each quarterly visit, participants were interviewed about self-reported contraceptive use and sexual behaviors and underwent HIV testing. Cox proportional hazards regression was used to assess the effect of injectable and oral hormonal contraceptive use on HIV acquisition.
  
  
  RESULTS
  The analysis included 2830 participants, of whom 106 became HIV infected (4.07 per 100 person-years). At baseline, 1546 (51%) participants reported using injectable contraceptives and 595 (21%) reported using oral contraceptives. HIV incidence among injectable, oral and nonhormonal contraceptive method users was 4.72, 2.68 and 3.83 per 100 person-years, respectively. Injectable contraceptive use was associated with a nonstatistically significant increased risk of HIV acquisition [adjusted hazard ratio (aHR)=1.17; 95% confidence interval (CI) 0.70, 1.96], while oral contraceptive use was associated with a nonstatistically significant decreased risk of HIV acquisition (aHR=0.76; 95% CI 0.37,1.55).
  
  
  CONCLUSIONS
  In this secondary analysis of randomized trial data, a marginal, but nonstatistically significant, increase in HIV risk among women using injectable hormonal contraceptives was observed. No increased HIV risk was observed among women using oral contraceptives. Our findings support the World Health Organization's recommendation that women at high risk for acquiring HIV, including those using progestogen-only injectable contraception, should be strongly advised to always use condoms and other HIV prevention measures.
  
  
  CONCLUSIONS
  Among Southern African women participating in an HIV prevention trial, women using injectable hormonal contraceptives had a modest increased risk of HIV acquisition; however, this association was not statistically significant. Continued research on the relationship between widely used hormonal contraceptive methods and HIV acquisition is essential.
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. Electronic address: jbalkus@fhcrc.org.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Balkus
authors.affiliation: Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Brown
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences and the Magee-Women's Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Hillier
authors.affiliation: FHI360, Durham, NC, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Coletti
authors.affiliation: HIV Prevention Research Unit, South Africa Medical Research Council, Durban, South Africa.
authors.forename: Gita
authors.initials: G
authors.lastname: Ramjee
authors.affiliation: University of Zimbabwe - University of California San Francisco Research Program, Harare, Zimbabwe.
authors.forename: Nyaradzo
authors.initials: N
authors.lastname: Mgodi
authors.affiliation: College of Medicine, University of Malawi, Blantyre, Malawi.
authors.forename: Bonus
authors.initials: B
authors.lastname: Makanani
authors.affiliation: Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.
authors.forename: Cheri
authors.initials: C
authors.lastname: Reid
authors.affiliation: University of North Carolina Project, Kamuzu Central Hospital, Lilongwe, Malawi.
authors.forename: Francis
authors.initials: F
authors.lastname: Martinson
authors.affiliation: National Institutes of Health, Bethesda, MD, USA.
authors.forename: Lydia
authors.initials: L
authors.lastname: Soto-Torres
authors.affiliation: Centre for the AIDS Program of Research in South Africa, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Congella, South Africa; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA.
authors.forename: Salim S
authors.initials: SS
authors.lastname: Abdool Karim
authors.affiliation: University of Zimbabwe - University of California San Francisco Research Program, Harare, Zimbabwe.
authors.forename: Zvavahera M
authors.initials: ZM
authors.lastname: Chirenje
mesh_terms: D000328:Adult; D017280:Condoms / Q000706:statistics & numerical data; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D003278:Contraceptives, Oral, Hormonal / Q000627:therapeutic use; D003692:Delayed-Action Preparations / Q000008:administration & dosage*; D015658:HIV Infections / Q000453:epidemiology* / Q000517:prevention & control; D006801:Humans; D015994:Incidence; D007273:Injections, Intramuscular; D008295:Malawi / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D013246:Sterilization, Tubal / Q000706:statistics & numerical data; D055815:Young Adult; D015024:Zambia / Q000453:epidemiology; D015030:Zimbabwe / Q000453:epidemiology
chemical_list: D003271:Contraceptive Agents, Female; D003278:Contraceptives, Oral, Hormonal; D003692:Delayed-Action Preparations
keywords: HIV infection; Hormonal contraception; Injectables; Oral contraceptive pills; Southern Africa; Women