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HIV incidence among post-partum women in Zimbabwe: risk factors and the effect of vitamin A supplementation

Humphrey, Jean Ha; Hargrove, John Wb; Malaba, Lucie Cd; Iliff, Peter Jb; Moulton, Lawrence Ha; Mutasa, Kudab; Zvandasara, Partsonc; Nathoo, Kusum Jc; Mzengeza, Faithd; Chidawanyika, Henryb; Zijenah, Lynn Sc; Ward, Brian Jethe ZVITAMBO Study Group

doi: 10.1097/01.aids.0000233578.72091.09
Epidemiology and Social

Objective: To test whether post-partum vitamin A supplementation can reduce incident HIV among post-partum women and identify risk factors for HIV incidence.

Design: 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 μmol/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.

Conclusion: 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.

From the aJohns Hopkins Bloomberg School of Public Health, Department of International Health, Baltimore, Maryland, USA

bZVITAMBO Project, Borrowdale, Harare, Zimbabwe

cUniversity of Zimbabwe College of Health Sciences, Harare, Zimbabwe

dUniversity of Zimbabwe Department of Nutrition, Harare, Zimbabwe

eResearch Institute of the McGill University Health Center, Montreal, Quebec, Canada.

*See Appendix.

Received 12 September, 2005

Accepted 6 April, 2006

Correspondence to J. Humphrey, ZVITAMBO Project, 1 Borrowdale Road, Borrowdale, Harare, Zimbabwe. E-mail:

© 2006 Lippincott Williams & Wilkins, Inc.