Risk factors for HIV-1 infection in a British population: lessons from a London sexually transmitted diseases clinic.

Between September 1985 and June 1988, 6923 people (4550 men and 2373 women) were tested for HIV-1 antibodies at a sexually transmitted disease clinic, London, UK. Of the 6923 individuals tested, 558 (8%) were seropositive, of whom 523 (94%) were men and 35 (6%) women. Of the seropositives, 84% were homosexual or bisexual men, 5% were intravenous drug users, 4% were heterosexual contacts of HIV seropositives, 4% had multiple risk factors, 2% were heterosexual contacts of central African partners and 1% were heterosexuals with no other risk factors. This prevalence pattern conforms to that observed in other industrialized nations. For the women, heterosexual intercourse with an HIV-infected partner, intravenous drug use and heterosexual contact with a partner from central Africa were the main risk factors for infection. The important risk factors among the men were heterosexual contact with an HIV-seropositive partner, being homosexual or bisexual, intravenous drug use and heterosexual contact with a resident from central Africa. heterosexual and homosexual transmission were implicated as the main routes for viral spread in this British population.