Methamphetamine use and sexual and injection risk behaviors among out-of-treatment injection drug users

Our primary objective was to examine the relationship between methamphetami ne use and sexual risk-taking behaviors-number of sexual partners, frequenc y of sexual behaviors with regular and casual partners, trading money or dr ugs for sex, and condom use-among male and female out-of-treatment injectio n drug users (OTIDUs). As a risk group for human immunodeficiency virus (HI V) transmission, we also investigated injection behaviors by methamphetamin e use. Data were collected from 1392 OTIDUs within the California counties of Fresno, Sacramento, and San Diego. Excluded from this cross-sectional su rvey were male OTIDUs engaging in sex with only or mostly men since 1978. I n bivariate analyses, we found that male OTIDUs with a history of methamphe tamine use had more sex partners and participated in more acts of anal inse rtive intercourse with casual partners and vaginal intercourse with regular and casual partners than male OTIDUs never using methamphetamines. In addi tion, a greater percentage of male OTIDUs using methomphetamines reported t rading sex for money or drugs. Methamphetamine-using female OTIDUs particip ated in more acts of vaginal intercourse with regular male sex partners tha n female OTIDUs never using methamphetamines. By multivariate logistic regr ession, we found methamphetamine use related to consistent condom use among male OTIDUs and among mole sex partners of female OTIDUs. Discriminant fun ction analyses revealed that sexual risk taking could be differentiated by methamphetamine use among male OTIDUs, methamphetamine use also correlated with using shared needles or syringes among male and female OTIDUs and was related to not always disinfecting used needles or syringes with bleach. Ou r findings suggest that methamphetamines may contribute to heterosexual HIV transmission.