Gay men who engage in substance use and sexual risk behaviour: a dual-risk group with unique characteristics.

'Recreational' substances used among men having sex with men, and their association with risky unprotected anal intercourse (RUAI) were examined--for the first time in Israel--in an internet-based questionnaire assessing knowledge, practices and motivation. Between March and May 2005, 2873 participants completed the entire questionnaire. Of the total, 669 (23%) reported RUAI during the last six months, and 1319 (46%) used substances during sex. Use of substance was significantly higher among those performing RUAI than those who did not (31.5% versus 26.4%, P=0.03). Involvement in both substance use and RUAI was reported by 366 participants (13%). HIV rates were higher in this dual-risk group (P<0.01), and individuals reported more partners in the last six months than those not part of this dual risk (11.6 versus 8.2, P=0.02). In multivariate analyses, Tel-Aviv residency, lower education, performing receptive RUAI, misperception of HIV transmission and limited negotiation skills were positively associated with this dual-risk behaviour.