Background and methods: The smoking of "crack" cocaine is thought to be associated with high-risk sexual practices that accelerate the spread of infection with the human immunodeficiency virus (HIV). We studied 2323 young adults, 18 to 29 years of age, who smoked crack regularly or who had never smoked crack. The study participants, recruited from the streets of inner-city neighborhoods in New York, Miami, and San Francisco, were interviewed and tested for HIV. This report presents the findings for the 1967 participants (85 percent) who had never injected drugs.
Results: Of the 1137 crack smokers, 15.7 percent were positive for HIV antibody, as compared with 5.2 percent of the 830 nonsmokers (prevalence ratio adjusted for the city, 2.4; 99 percent confidence interval, 1.7 to 3.6). The prevalence of HIV was highest among the crack-smoking women in New York (29.6 percent) and Miami (23.0 percent). Of the 283 women who had sex in exchange for money or drugs, 30.4 percent were infected with HIV as compared with 9.1 percent of the 286 other women (prevalence ratio, 3.1; 99 percent confidence interval, 1.9 to 5.1); of the 91 men who had anal sex with other men, 42.9 percent were infected with HIV as compared with 9.3 percent of the 582 men who did not have anal sex with other men (prevalence ratio, 4.7; 99 percent confidence interval, 3.0 to 7.4). In multivariable analyses, these high-risk sexual practices accounted for the higher prevalence of HIV infection among the crack smokers, as compared with those who did not smoke crack. Women who had recently had unprotected sex in exchange for money or drugs were as likely to be infected as men who had had sex with men (40.9 percent vs. 42.9 percent).
Conclusions: In poor, inner-city communities young smokers of crack cocaine, particularly women who have sex in exchange for money or drugs, are at high risk for HIV infection. Crack use promotes the heterosexual transmission of HIV.