Increased risk of infection with hepatitis A and B viruses in men with a history of syphilis: relation to sexual contacts.

Serum samples from 269 men with at least one episode of syphilis were tested for the presence of markers of hepatitis A and B viruses. The patients were divided into three groups: 177 homosexual men, 35 heterosexual men, and 57 men with unknown sexual contacts. The incidence of hepatitis B surface antigen or its antibody (anti-HBs) was three times greater in the homosexual men (67%) than in the men with unknown sexual contacts (25%) and the heterosexual men (23%). The incidence of anti-HBs increased with age, reaching 84% in the homosexual men 40-49 years of age. A positive correlation was found between the presence of markers of hepatitis A and B viruses and the number of episodes of syphilis in younger homosexual men (P less than 0.01). Antibody to hepatitis A virus was found in 36% of the homosexual men, 18% of the men with unknown sexual contacts, and 20% of the heterosexual men. Only one patient was found to have IgM antibodies to hepatitis A virus.