HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION AND GENITAL WARTS AS RISK-FACTORS FOR ANAL INTRAEPITHELIAL NEOPLASIA IN HOMOSEXUAL MEN

The incidence of anal intraepithelial neoplasia (AIN) was studied in a group of 210 homosexual and bisexual men. The presence of genital war ts and human immunodeficiency virus (HIV) infection was assessed as ri sk factors for the development of AIN. In all, 74 (35 per cent) of the group had histological evidence of AIN. The relative risk of being po sitive for HIV on AIN (relative to being negative for HIV) was 1.58 (9 5 per cent confidence interval (c.i.) 1.01-2.48). The relative risk of anal warts on AIN (relative to absence of anal warts) was 4.70 (95 pe r cent c.i. 1.81-12.20). Logistic regression analysis showed no signif icant interactive effect between HIV and anal warts on the risk of AIN . It is concluded from the results of a Mantel-Haenzel analysis that t he presence of anal warts and HIV infection are independent risk facto rs for the development of AIN in homosexual and bisexual men.