Risk factors for human immunodeficiency virus type 1 (HIV-1) infection in patients at a sexually transmitted disease clinic in New York City.

Patients who attended a sexually transmitted disease clinic in New York City in 1987 were offered enrollment in a nonblinded study to estimate human immunodeficiency virus type 1 (HIV-1) seroprevalence in adults with multiple sexual partners and to determine risk factors associated with HIV-1 infection. In addition, a blinded serosurvey of a representative sample of patients was performed to obtain an unbiased estimate of seroprevalence in clinic attendees. The seroprevalence in the blinded serosurvey was 7.5% (26/348), while the seroprevalence of the 1,201 volunteers for the nonblinded study was 11.2%. For men in the nonblinded study, the risk behaviors most strongly associated with HIV-1 infection were intravenous drug use, sexual contact with another man, and sexual contact with a female intravenous drug user. For women, intravenous drug use and sexual contact with a man at risk for HIV-1 infection (an intravenous drug user or a bisexual) were most important. The seroprevalence among persons who denied all high-risk behavior was 1% (7/723). The results of this study, conducted in a city with one of the nation's highest reported cumulative incidences of acquired immunodeficiency syndrome, suggest that HIV-1 infection in clinic attendees was primarily limited to intravenous drug users, homosexual/bisexual men, and the sexual partners of these two groups.