title: Hormonal contraception and the risk of HIV acquisition among women in South Africa.
abstract: OBJECTIVE
  To evaluate the effect of hormonal contraception including combined oral contraceptives (COCs), and the injectable progestins depo-medroxyprogesterone acetate (DMPA) and norethisterone enanthate (Net-En) on the risk of HIV acquisition among women in South Africa.
  
  
  METHODS
  We analyzed data from 5567 women aged 16-49 years participating in the Carraguard Phase 3 Efficacy Trial. Participants were interviewed about contraceptive use and sexual behaviors and underwent pelvic examinations and HIV testing quarterly. We used marginal structural Cox regression models to estimate the effect of hormonal contraception exposure on HIV acquisition risk among women overall and among young women (16-24 years) in particular.
  
  
  RESULTS
  Two hundred and seventy participants became HIV-infected (3.7 per 100 woman-years); HIV incidence was 2.8, 4.6, 3.5 and 3.4 per 100 woman-years in the COC, DMPA, Net-En and nonhormonal contraceptive groups, respectively (P = 0.09). The adjusted hazard ratios (AHRs) were 0.84 [95% confidence interval (CI) 0.51-1.39], 1.28 (95% CI 0.92-1.78) and 0.92 (95% CI 0.64-1.32) among COC, DMPA and Net-En users, respectively, compared with the nonhormonal group controlling for covariates. Age modified the effect of hormonal contraception on HIV acquisition risk; among young women, the AHRs were 1.02 (95% CI 0.46-2.28) for COCs, 1.68 (95% CI 0.96-2.94) for DMPA and 1.36 (95% CI0.78-2.35) for Net-En users.
  
  
  CONCLUSIONS
  In this study conducted among South African women, hormonal contraception did not significantly increase the risk of HIV acquisition. However, the effect estimate does not rule out a moderate increase in HIV risk associated with DMPA use found in some other recent studies.
authors.affiliation: FHI 360, Durham, North Carolina 27713, USA. cmorrison@fhi360.org
authors.forename: Charles S
authors.initials: CS
authors.lastname: Morrison
authors.forename: Stephanie
authors.initials: S
authors.lastname: Skoler-Karpoff
authors.forename: Cynthia
authors.initials: C
authors.lastname: Kwok
authors.forename: Pai-Lien
authors.initials: PL
authors.lastname: Chen
authors.forename: Janneke
authors.initials: J
authors.lastname: van de Wijgert
authors.forename: Marlena
authors.initials: M
authors.lastname: Gehret-Plagianos
authors.forename: Smruti
authors.initials: S
authors.lastname: Patel
authors.forename: Khatija
authors.initials: K
authors.lastname: Ahmed
authors.forename: Gita
authors.initials: G
authors.lastname: Ramjee
authors.forename: Barbara
authors.initials: B
authors.lastname: Friedland
authors.forename: Pekka
authors.initials: P
authors.lastname: Lahteenmaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000890:Anti-Infective Agents / Q000008:administration & dosage*; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage*; D005260:Female; D006679:HIV Seropositivity / Q000453:epidemiology / Q000635:transmission*; D006801:Humans; D015994:Incidence; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage*; D008875:Middle Aged; D009640:Norethindrone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D016017:Odds Ratio; D011247:Pregnancy; D016016:Proportional Hazards Models; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D013019:South Africa / Q000453:epidemiology; D014622:Vaginal Creams, Foams, and Jellies / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D000890:Anti-Infective Agents; D003278:Contraceptives, Oral, Hormonal; D014622:Vaginal Creams, Foams, and Jellies; D017258:Medroxyprogesterone Acetate; C024319:norethindrone enanthate; D009640:Norethindrone