Question 8: Do risk factors for HIV infection acquisition and transmission differ for women compared with men in methadone maintenance treatment?

Answer: Yes. Despite nearly equal HIV infection rates for men and women in drug treatment, female injection drug users differ from males in the types and contexts of their risk behaviors. While the main HIV infection risk for both male and female injection drug users is needle sharing, women frequently support themselves and their addiction habit through sex work and are more likely to have an injection drug user as a sexual partner. The most common needle-sharing context for women is with their sex partners.

In addition, women may transmit HIV infection to their infants in utero, during delivery, or through breastfeeding. Women in methadone treatment need HIV infection prevention programs that take these gender differences into account.

Research Highlights

• Patterns of needle sharing are different for males and females. Women tend to share needles in the context of a sexual relationship. This type of needle sharing may be more difficult to change than other types of injection risk behavior because the perception of risk or ability to negotiate safe needle use by women may be limited. In research conducted among 19,716 males and 6,609 females in the National AIDS Demonstration Research (NADR) project addressing street-recruited injection drug users, women were more likely than men to share needles with their sex partners. The majority of the participants injected only heroin or heroin in combination with cocaine (Brown and Weissman, 1994).
  
  Research in other countries has shown a tendency for female injection drug users to share needles with their sex partners. For example, women in Glasgow, Scotland, were frequently injected with used needles and syringes from their partners (Barnard, 1993).
• Sexual risk behavior has been shown to be less likely to change among both male and female injection drug users than needle-sharing risk behavior. In addition, women who inject drugs are less likely than men to be in control of safer sex practices, such as condom use. Although methadone maintenance treatment may reduce drug use and prostitution or the exchange of sex for drugs, women may be at risk for HIV infection by their habitual sex partners. Female injection drug users tend to have drug users as sex partners, even after enrollment in treatment, and are not likely to practice safer sex with these partners. HIV risk reduction programs for women in methadone maintenance treatment must take into account the social and interpersonal context of sexual risk behavior in order to be effective (Hartel, 1994).
• Women with HIV who are maintained on methadone may improve their access to medical care for HIV infection and disease and possibly reduce their chance of transmitting HIV to infants in utero. Both zidovudine (AZT) and nevaripine have been shown to reduce significantly the risk of mother-to-infant transmission of HIV infection (Brocklehurst and Volmink, 2002).
• It is likely that some infants are infected during labor and delivery or after delivery through breastfeeding. Careful attention to factors that can place the infant at risk during birth and afterwards is needed to further reduce infant infection. In areas with a high community level of HIV infection among injection drug users, methadone programs often incorporate HIV primary health care services into the treatment program through onsite services or linkages to services nearby. These services often include obstetrical care by providers skilled in working with HIV-infected women (Finnegan et al., 1993).

Differences Between Men and Women in HIV Infection Rates and Risk Behaviors–Figure 22 illustrates that overall HIV infection rates are roughly the same for males and females entering drug abuse treatment in the United States: 5.4 percent for males and 4.4 percent for females. These rates vary greatly (0 to 48 percent) by geographic area, with the highest rates found in urban centers that have the greatest density of injection drug users (Allen, Onorato, and Green, 1992).

Figure 22 illustrates that overall HIV infection rates are roughly the same for men and women entering drug abuse treatment in the United States: 5.4 percent for men and 4.4 percent for women. These rates vary greatly (0 to 48 percent) by geographic area, with the highest rates found in urban centers that have the greatest density of injection drug users (Allen et al., 1992).

In research conducted in New York, NY, among 452 methadone-recruited injection drug users early in the HIV epidemic, having an injection drug user as a sex partner was associated with HIV infection status independent of or in addition to injection risk behavior. In this same study, women reported a higher level of sexual risk behavior than men: 57 percent of women compared with 45 percent of men reported one or more injection drug users as sex partners since 1978. In addition, women were more likely than men to have engaged in sex work: 23 percent of women compared with 5 percent of men (Schoenbaum, Hartel, Selwyn, et al., 1989).

References

Allen D, Onorato I, Green T. HIV infection in intravenous drug users entering drug treatment, United States, 1988 to 1989. American Journal of Public Health 1992;82:541-46.

Barnard, M. Needle sharing in context: patterns of sharing among men and women injectors and HIV risks.Addiction 1993;88:805-12.

Brocklehurst P, Volmink J. Antiretrovirals for reducing the risk of mother-to-child transmission of HIV infection. The Cochrane Database of Systematic Reviews, Issue 2, 2002.

Brown V, Weissman G. Women and men injection drug users: an updated look at gender differences and risk factors. In: Brown B, Beschner G (eds.). Handbook on Risk of AIDS: Injection Drug Users and Sexual Partners.Westport, CT: Greenwood Press, 1994.

Connor E, Sperling R, Gelber R, Kiselev P, Scott G, O'Sullivan MJ, et al. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment. New England Journal of Medicine 1994;331:1173-80.

Finnegan L, Davenny K, Hartel D. Drug use in HIV-infected women. In: Johnson M, Johnstone F (eds.). HIV Infection in Women. London: Churchill Livingstone, 1993.

Hartel D. Context of HIV Risk Behavior Among Female Injecting Drug Users and Female Sexual Partners of Injecting Drug Users. NIDA Research Monograph Series 143. Rockville, MD: National Institute on Drug Abuse, 1994.

Schoenbaum EE, Hartel D, Selwyn P, Klein RS, Davenny K, Rogers M, et al. Risk factors for HIV infection in intravenous drug users. New England Journal of Medicine 1989;321:874-79