A case-control study of risk factors for sporadic hepatitis C virus infection in the southwestern United States

OBJECTIVE: We performed a case-control study to evaluate risk factors and p ossible modes of transmission for hepatitis C virus (HCV) infection in pati ents with no history of blood transfusion or injection drug use. METHODS: Study subjects were selected from among patients seen in gastroent erology outpatient clinics at a university medical center in the southweste rn United States. The study group consisted of 58 patients (12%) with chron ic HCV infection who reported no history of transfusion or injection drug u se, among a total of 477 patients evaluated for a positive HCV antibody tes t. These 58 patients were matched by age, ethnicity, and gender with 58 con trol patients diagnosed with gastroesophageal reflux attending the same cli nics. Patients and controls were subjected to structured interviews and rev iew of medical records. RESULTS: A variety of variables were significantly associated with increase d risk of sporadic HCV infection, including a history of tattoos, needlesti ck exposure, a history of sexually transmitted disease, intercourse with an injection drug user, five or more lifetime sexual partners, intercourse du ring menses (for women), lower income, and heavy alcohol intake (>60 g/day) . Multivariate analysis identified a history of sexually transmitted diseas e, heavy alcohol intake, and the presence of a tattoo as independent risk f actors for sporadic HCV. In addition, six cases and one control had a histo ry of needlestick exposure. Of the cases, 88% had at least one of these fou r risk factors, as compared with 26% of controls (odds ratio = 16.5; 95% co nfidence interval = 4.0-68.8). CONCLUSIONS: A history of sexually transmitted disease, heavy alcohol intak e, the presence of tattoos, and a history of needlestick exposure were iden tified as risk factors for sporadic hepatitis C in this case-control study. If we include all patients with a history of blood transfusion or injectio n drug use, only 2% of the total 477 HCV patients had no identified risk fa ctors. (C) 1999 by Am. Cell. of Gastroenterology.