title: HIV incidence among post-partum women in Zimbabwe: risk factors and the effect of vitamin A supplementation.
abstract: OBJECTIVE
  To test whether post-partum vitamin A supplementation can reduce incident HIV among post-partum women and identify risk factors for HIV incidence.
  
  
  METHODS
  Randomized, placebo-controlled trial
  
  
  METHODS
  Between November 1997 and January 2001, 14,110 women were randomly administered 400,000 IU vitamin A or placebo within 96 h post-partum. HIV incidence was monitored among 9562 HIV-negative women.
  
  
  RESULTS
  Cumulative incidence was 3.4% [95% confidence interval (CI), 3.0-3.8] and 6.5% (95% CI, 5.7-7.4) over 12 and 24 months post-partum, respectively. Vitamin A supplementation had no impact on incidence [hazard ratio (HR), 1.08; 95% CI, 0.85-1.38]. However, among 398 women for whom baseline serum retinol was measured, those with levels indicative of deficiency (< 0.7 micromol/l, 9.2% of those measured) were 10.4 (95% CI, 3.0-36.3) times more likely to seroconvert than women with higher concentrations. Furthermore, among women with low serum retinol, vitamin A supplementation tended to be protective against incidence (HR, 0.29; 95% CI, 0.03-2.60; P = 0.26), although not significantly so, perhaps due to limited statistical power. Severe anaemia (haemoglobin < 70 g/l) was associated with a 2.7-fold (95%CI, 1.2-6.1) greater incidence. Younger women were at higher risk of HIV infection: incidence declined by 5.7% (2.8-8.6) with each additional year of age.
  
  
  CONCLUSIONS
  Among post-partum women, a single large-dose vitamin A supplementation had no effect on incidence, although low serum retinol was a risk factor for seroconversion. Further investigation is required to determine whether vitamin A supplementation of vitamin-A-deficient women or treatment of anaemic women can reduce HIV incidence.
authors.affiliation: Johns Hopkins Bloomberg School of Public Health, Department of International Health, Baltimore, Maryland, USA. jhumphrey@zvitambo.co.zw
authors.forename: Jean H
authors.initials: JH
authors.lastname: Humphrey
authors.forename: John W
authors.initials: JW
authors.lastname: Hargrove
authors.forename: Lucie C
authors.initials: LC
authors.lastname: Malaba
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Iliff
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Moulton
authors.forename: Kuda
authors.initials: K
authors.lastname: Mutasa
authors.forename: Partson
authors.initials: P
authors.lastname: Zvandasara
authors.forename: Kusum J
authors.initials: KJ
authors.lastname: Nathoo
authors.forename: Faith
authors.initials: F
authors.lastname: Mzengeza
authors.forename: Henry
authors.initials: H
authors.lastname: Chidawanyika
authors.forename: Lynn S
authors.initials: LS
authors.lastname: Zijenah
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Ward
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D015994:Incidence; D017533:Marital Status; D009790:Occupations / Q000706:statistics & numerical data; D010298:Parity; D011181:Postnatal Care / Q000379:methods*; D011247:Pregnancy; D012307:Risk Factors; D012725:Sexual Behavior; D012959:Socioeconomic Factors; D014801:Vitamin A / Q000097:blood / Q000627:therapeutic use*; D015030:Zimbabwe / Q000453:epidemiology
chemical_list: D006454:Hemoglobins; D014801:Vitamin A