Vitamin A and risk of HIV-1 seroconversion among Kenyan men with genital ulcers

Background: Vitamin A is involved in normal immune function and the mainten ance of mucosal integrity through complex effects on cellular differentiati on. Objective: We sought to determine whether serum vitamin A levels were assoc iated with altered susceptibility to primary infection with HIV-1 in men wi th high-risk sexual behaviour and genital ulcers who presented for treatmen t at an STD clinic in Nairobi, Kenya. Methods: HIV-1 seronegative men were prospectively followed. Vitamin A leve ls at study entry were compared among 38 men who HIV-1 seroconverted versus 94 controls who remained HIV seronegative. Results: Vitamin A deficiency (retinol less than 20 mug/dl) was very common and was present in 50% of HIV-1 seroconverters versus 76% of persistent se ronegatives. Seroconversion was independently associated with a retinol lev el greater than 20 mug/dl (HR 2.43, 95% CI 1.25-4.70, P = 0.009), and a gen ital ulcer aetiology caused by Haemophilus ducreyi (HR 3.49, 95% CI 1.03-11 .67, P = 0.04. Circumcision was independently associated with protection (H R 0.46, 95% CI 0.23-0.93, P = 0.03). Conclusion: Vitamin A deficiency was not associated with an increased risk of HIV-1 infection among men with concurrent STD. A decreased risk of HIV-1 seroconversion was independently associated with lower retinol levels. The effects of vitamin A on macrophage and lymphoid cell differentiation may p aradoxically increase mucosal susceptibility to HIV-1 in some vulnerable in dividuals, such as men with genital ulcers. Lack of circumcision and chancr oid are confirmed as important co-factors for heterosexual HIV-1 transmissi on. The role of vitamin A in heterosexual HIV-1 transmission requires furth er study. (C) 2001 Lippincott Williams & Wilkins.