Gender differences in injection risk behaviors at the first injection episode.

Objectives: To examine gender differences in drug injection equipment sharing at injecting initiation.

Methods: Young injecting drug users (IDUs) in New York City February 1999-2003 were surveyed about injection risk behaviors and circumstances at initiation. Analyses were gender-stratified and excluded participants who initiated alone. Multiple logistic regression estimated adjusted odds ratios.

Results: Participants (n=249) were 66% male and 82% White. Mean initiation age was 19.2; mean years since initiating was 3.0. Women were significantly more likely to cite social network influence as a reason for initiating, to have male and sex partner initiators, and to share injecting equipment than men. Among women, sharing any injection equipment was associated with initiation by a sex partner and having > or =2 people present. Among men, being injected by someone else predicted sharing any injection equipment, while using a legally obtained syringe was protective.

Conclusions: Social persuasion stemming from sexual and/or social relationships with IDUs may increase women's risk of sharing injection equipment at initiation, and consequently, their early parenteral risk of acquiring blood-borne infections. Interventions should focus on likely initiates, especially women in injecting-discordant sex partnerships, and IDUs (potential initiators).