Risk factors of Kaposi's sarcoma among HIV infected homosexuals

Background: To study behavioral risk factors of Kaposi's sarcoma (KS) among HIV infected homosexuals in Boudeaux; southwest France. Methods: A case-control study was performed within the Aquitaine Cohort. Ca ses of KS surviving in 1995 and homosexuals were systematically enrolled. F or each case, two controls were selected among homosexuals surviving in the cohort. Cases and controls were matched on year of diagnosis of HIV infect ion. Data collection was based on a self administered questionnaire focusin g on use of recreational drugs, detailed sexual practices and sexually tran smitted diseases irt the year preceeding the diagnosis of HIV infection, in the year after the HIV diagnosis mid in the year preceeding the diagnosis of KS (or an equivalent period of time for controls). Results: Twelve cases were matched to 2 controls, 15 cases to one control a nd 13 cases remained unmatched Matched analysis identified an association b etween KS and regular sexual partner (odds ratio=0.07; 95% confidence inter val: 0.01-0.52 and p<0.01) and active and passive oro-anal intercourse befo re HIV diagnosis mid before KS diagnosis (p=0.01). In the unmatched analysi s including all cases, we found an association between KS and the overall n umber of sexual partners (p<0.03) for all periods of interest. Conclusions: This case-control study identified sexual practices in favor o f a sexually transmitted agent of KS.