cases involving users who were also gay and bisexual men continued for several years.
As discussed above, sexual transmission from intravenous drug users to their sexual partners may pose a greater risk for women than for men. The likelihood that an injection drug user has an injection drug-using partner is generally quite high, particularly among women (Mandell et al., 1994; Ross et al., 1992; Dwyer et al., 1994). As estimated, 75 to 90 percent of female injection drug users have a male injection drug-using partner compared with 20 to 50 percent of male users who have female drug-using partners (Cohen et al., 1989; Mondanaro, 1990; Donoghoe, 1992). In one survey in New York City (Fordyce et al., 1991), 2 percent of all currently sexually active women in 1990 reported that they knew they had a sexual partner who injected drugs. In another survey of risk factors for HIV infection among female injection drug users in methadone treatment (Schoenbaum et al., 1989), the number of male sexual partners who used drugs was strongly associated with HIV infection and was the only risk factor associated with acquisition of HIV for those women who had not used drugs since 1982.
Female sexual partners of male injection drug users may use sex as a way to obtain drugs (Donoghoe, 1992). They may also share needles with partners, thus exposing themselves to two sources of risk. Such women may be at even greater risk for sexual transmission of HIV than female partners of male injection drug users who do not themselves inject drugs—who may, in fact, be less likely to use condoms with male injection drug-using partners than with their partners who do not inject (Klee et al., 1990; Cohen, 1991; Worth, 1989).
Trading sex for drugs or money increases infection rates between injection drug users and the heterosexual community. Approximately 25 percent of female injection drug users engage in prostitution (Cohen et al., 1989; Donoghoe, 1992; Saxon et al., 1991). According to one survey in Baltimore (Astemborski et al., 1994), women who traded sex for drugs with more than 50 men over the 10 years prior to entry into the study were more likely to be infected with HIV than other female injection drug users. This finding remained significant after controlling for a range of risk factors for HIV.
In addition, women who use crack (whether or not they use injection drugs) may also trade sex for drugs and may also serve to bridge the gap between injection drug use and the heterosexual risk of HIV transmission (Des Jarlais and Friedman, 1988b; Edlin et al., 1994). Through acquisition of large numbers of partners, many of whom are also injection drug users, women who engage in this practice also expose themselves to HIV. This problem may be confounded by the profound disinhibition associated with cocaine use, resulting in little concern for safe sex or safe needle use (Donoghoe, 1992; Hartel et al., 1992). This may be due in part to the direct effects of