The relationship of sexual dyad and personal network characteristics and individual attributes to unprotected sex among young injecting drug users.

We examine in the heterosexual partnerships (dyads) of IDUs the correlates of engaging in unprotected sex on three levels: individual attributes, social network characteristics, and dyad characteristics. Unprotected sex was significantly less likely to occur in dyads where the participant injected daily or had high safe-sex attitude scores, and in dyads where both members encouraged each other to use condoms. Unprotected sex was significantly more likely to occur in dyads that smoked crack together, shared needles with each other, and where the participant knew that the sex partner had concurrent sex partners. In the sexual dyads of IDUs there is a combined risk of unsafe injecting and unsafe sex. Both injecting and sexual risk, and their combination need to be addressed in interventions that target the sexual partnerships of IDUs. Such interventions should also aim to reduce injected and non-injected crack and other stimulant use associated with high-risk sex.