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K. J. P. Craib*, C. H. Sherlock, R. S. Hogg, M. V. O'Shaughnessy, and M. T. Schechter for the Vancouver Lymphadenopathy-AIDS Study (VLAS).
BC Ctr. for Excellence in HIV/AIDS, St. Paul's Hosp., Vancouver, British Columbia, Canada.
Background:Our objective was to determine HCV prevalence and identify risk factors for HCV infection in a cohort of sexually active homosexual men in Vancouver, BC.
Methods:The most recent serum samples (obtained during 1982—98) from each of 662 VLAS participants were tested for HCV antibody using EIA1, EIA2, and RIBA. Data regarding demographic variables, sexual practices, substance use, and history of infectious diseases were obtained from self-administered questionnaires completed during 1982—85. Case-control comparisons between HCV+and HCV-men were conducted. Multivariate logistic regression was used to identify independent risk factors associated with HCV positivity.
Results:A total of 39 of 662 participants (5.9%) were identified as HCV+. HCV prevalence was significantly higher among HIV+men compared to HIV-men (31/352 = 8.8% vs. 8/310 = 2.6%; p < 0.001). HCV+men were more likely to report higher numbers of male sexual partners in the previous year (>20 partners: 74% vs. 48%; p = 0.002) and in their lifetime (>100 partners: 82% vs. 64%; p = 0.024) and more likely to report insertive fisting (49% vs. 27%; p = 0.003), oral-anal contact (90% vs. 73%; p = 0.019), and receptive anal intercourse (62% vs. 45%; p = 0.043). HCV+men were more likely to report using injection drugs during their lifetime (51% vs. 3%; p < 0.001) and use of the following substances during the prior year: MDA (64% vs. 37%; p < 0.001), LSD (49% vs. 26%; p = 0.002), amphetamine (28% vs. 14%; p = 0.013), cocaine (46% vs. 30%; p = 0.029), and tobacco (67% vs. 48%; p = 0.027). Nineteen (49%) of the 39 HCV+cases reported never injecting drugs. Comparisons of these 19 HCV+, non-IDU with 589 HCV-, non-IDU revealed oral-anal contact (95% vs. 72%; p = 0.029) and insertive fisting (51% vs. 26%; p = 0.012) as significant risk factors for HCV acquisition. Multivariate analysis of all participants revealed injection drug use (p < 0.001), HIV positivity (p = 0.042), and number of male sexual partners in the previous year (p = 0.066) to be independent risk factors for HCV positivity.
Conclusions:Not surprisingly, a history of injection drug use was a significant risk factor for HCV infection. However, 49% of HCV+men in this cohort did not report injection drug use. Among non-IDU men, specific sexual practices were identified as significant risk factors for HCV positivity. These data provide evidence of independent sexual transmission of HCV among homosexual men, accounting for the approximately 50% of cases in this cohort.
© 8th Conference on Retroviruses and Opportunistic Infections