Sex- and drug-related risk among populations of younger and older injection drug users in adjacent neighborhoods in San Francisco

The objective of this study was to compare drug injection- and sex-related risk behaviors of younger and older injection drug users (IDUs) in two adja cent neighborhoods. IDUs were recruited from street settings in two adjacen t neighborhoods in San Francisco in April, 1997. All participants were inte rviewed using a standardized questionnaire and were tested for HIV antibodi es. Drug injection- and sex-related risk behaviors were compared between yo unger IDUs (<30 years; n = 56) and older IDUs (greater than or equal to 30 years; n = 116). Younger IDUs were more likely to be white, be homeless, ha ve injected amphetamines, and have been arrested in the past year, Older ID Us were more likely to be African American and smoke crack cocaine; they ha d injected a mean of Is years longer. Younger IDUs were more likely to have shared syringes in the past month (52% versus 10%; p < .05), report drug o verdose in the past lj months (39% versus 7%; p < .05), and to have had unp rotected vaginal intercourse in the past 6 months (77% versus 53%; p < .05) . After controlling for confounding factors using logistic regression analy sis, all these associations remained significant. There is an urgent need f or innovative prevention programs that target younger, homeless IDUs.