Risk factors for hepatitis C virus infection among nonintravenous-drug- using heterosexuals attending a clinic for sexually transmitted disease in Italy

Objective: To evaluate prevalence of and risk factors for hepatitis C virus (HCV) infection and the role of genital ulcer disease in the sexual transmission of HCV among 1280 nonintravenous-drug-using heterosexuals attending a sexually transmitted disease clinic. Methods: Serum samples were tested by a third-generation enzyme-linked immunosorbent assay (ELISA) test. Reactive sera were confirmed using a RIBA assay. The independent effect of different variables on the likelihood to be anti-HCV positive was assessed by multiple logistic regression analysis. Results: The overall anti-HCV prevalence was 4.9%, a rate nearly ten times as high as the 0.5% recently found in a national sample of young male adults 18 to 26 years old. The prevalence was 9.6% in subjects with positive syphilis serology and 3.8% in those without a history of sexually transmitted disease. Multiple logistic regression analysis showed that age greater than 34 years (OR 2.9; 95% Cl 1.1-7.6), low educational level (OR 2.0; 95% Cl 1.1-3.5), positive syphilis serology (OR 2.1; 95% Cl 1.04-4.1), and anti-HIV positivity (OR 4.6; 95% Cl 1.2-18.7) were all independent predictors of HCV infection. Conclusions: These findings are consistent with sexual transmission of HCV. Syphilis infection may be a cofactor in HCV transmission or, alternatively, may be a strong indicator of high-risk sexual behavior.