Potential risk factors for the transition to injecting among non-injecting heroin users: a comparison of former injectors and never injectors.

AIMS: To compare potential risk factors for the transition to injecting among non-injecting heroin users (NIUs) with different injecting histories. DESIGN: Cross-sectional data from baseline structured interviews with NIUs in a study on transitions to injecting. Sample recruited by outreach or chain-referral in New York City (NYC), 1996-1998. SETTING: Recruitment of sample and interviews conducted in a NYC neighborhood where many drug users reside and/or use drugs. PARTICIPANTS: Of 575 NIUs, 67% had never injected; 16% had injected one to nine times (infrequent former injectors (IFI)); and 18% 10 or more times (frequent former injectors (FFI)). MEASUREMENTS: Controlling for age and race/ethnicity, adjusted odds ratios were estimated in multivariate logistic regression, and differences in means tested by ANCOVA. FINDINGS: FFI (compared to never injectors and IFI) were more likely: to be homeless; to be unemployed; to be long-time users; to be younger at first heroin use; to not have initiated heroin use through non-injected routes; to not be afraid of injecting themselves with needles; to sniff heroin with former IDUs; and, for both men and women separately, to have sex partners who were former IDUs. Both FFI and IFI were twice as likely as never injectors to perceive that their friends thought that it was "OK" to inject drugs. CONCLUSIONS: FFI have multiple individual and network characteristics that may increase their risk of injecting drugs. Interventions among NIUs to prevent transitions to injecting need to ascertain NIUs' injecting history and address the many potential risks that FFI have for resuming injecting drug use.

Drug scene roles and HIV risk.

AIMS: Drug scenes (social and spatial drug-using and drug-selling environments) have complex role structures. Many drug injectors earn money or drugs as drug or syringe sellers, hit doctors (people who help others to inject) commercial sex workers, or in other roles. This paper aims to measure "role behaviors" of drug injectors; describe which drug injectors are more likely to engage in such role behaviors; and to determine whether roles are related to elements of HIV risk. DESIGN: Cross-sectional study of drug injectors. SETTING: Bushwick, a section of Brooklyn, New York, a major location for injection drug use and drug sales. PARTICIPANTS: Seven hundred and sixty-seven street-recruited drug injectors. MEASUREMENTS: Participants were interviewed about their roles, behaviors, socio-demographics and risk networks; sera were collected and assayed for HIV and hepatitis B core antibody. FINDINGS: Socio-demographic variables are related to role-holding in complex ways. Economic need is generally associated with engaging in drug-scene role behaviors. Holders of these roles are at greater behavioral and network risk for HIV and other blood-borne infections than are other drug injectors. They also engage in extensive communication with other drug users, including discussion of HIV risk reduction. CONCLUSION: Role behaviors can be measured in quantitative studies, and seem to be related to HIV risk. Role-holders may be strategic targets for risk-reduction campaigns. It seems feasible and advisable to measure drug scene role-holding in research on drug users.

Sociometric risk networks and risk for HIV infection.

OBJECTIVES: This study examined whether networks of drug-injecting and sexual relationships among drug injectors are associated with individual human immunodeficiency virus (HIV) serostatus and with behavioral likelihood of future infection. METHODS: A cross-sectional survey of 767 drug injectors in New York City was performed with chain-referral and linking procedures to measure large-scale (sociometric) risk networks. Graph-theoretic algebraic techniques were used to detect 92 connected components (drug injectors linked to each other directly or through others) and a 105-member 2-core within a large connected component of 230 members. RESULTS: Drug injectors in the 2-core of the large component were more likely than others to be infected with HIV. Seronegative 2-core members engaged in a wide range of high-risk behaviors, including engaging in risk behaviors with infected drug injectors. CONCLUSIONS: Sociometric risk networks seem to be pathways along which HIV travels in drug-injecting peer groups. The cores of large components can be centers of high-risk behaviors and can become pockets of HIV infection. Preventing HIV from reaching the cores of large components may be crucial in preventing widespread HIV epidemics.

High-risk personal networks and syringe sharing as risk factors for HIV infection among new drug injectors.

In a cross-sectional study of 174 new injecting drug users (IDUs) in New York City who had injected for < or = 6 years, we examined whether those who both share syringes and have personal risk networks that include high-risk injectors are particularly likely to be infected with HIV. Subjects were street recruited between July 1991 and January 1993, were interviewed about their risk behaviors in the prior 2 years and their personal risk networks with other IDUs in the prior 30 days, and were tested for HIV; 20% were HIV seropositive. Among those who both shared syringes and had a personal risk network member who injected more than once a day, 40% were HIV seropositive (versus 14% for others, p < 0.001). In simultaneous multiple logistic regression, the interaction of both sharing syringes and having a personal risk network member who injected more than once a day remained independently and significantly associated with being HIV seropositive (OR, 3.57; 95% CI, 1.22, 10.43; p < 0.020), along with Latino race/ethnicity and exchanging sex for money or drugs. These findings suggest that the combination of sharing syringes with having a high-risk personal network is a risk factor for HIV infection among new IDUs. Studies of risk factors for HIV infection among new IDUs and interventions to reduce the spread of HIV among them should focus on their risk networks as well as their risk behaviors.

Self-reports of HIV risk behavior by injecting drug users: are they reliable?

While most studies of AIDS risk behavior rely on self-reports, few studies have assessed the reliability of these reports. The present study examines self-reports of drug-related and sexual risk behavior among pairs of injecting drug users (IDUs) recruited from the streets in New York City. Since both members of the pair were interviewed, it was possible to compare their responses in order to assess reliability. Subjects reported on their contacts' demographic data (age, gender, race/ethnicity) and on shared risk behaviors, including syringe sharing. Despite the private and/or illegal nature of AIDS risk behaviors, IDU subjects were generally reliable in their reports of both demographic and AIDS risk behaviors.

Consistent condom use in relationships between seropositive injecting drug users and sex partners who do not inject drugs.

OBJECTIVES: To study how condom use in injecting drug users' (IDU) relationships differs according to whether they are HIV-infected, and to whether their sex partner is an IDU. DESIGN AND METHODS: A total of 317 street-recruited IDU were HIV-antibody tested and interviewed about 421 relationships with particular sex partners. RESULTS: Condoms were consistently (100%) used in sex between partners (during the previous 30 days) in 33% of these relationships, and their use was significantly more frequent in relationships of seropositive IDU and in relationships with non-IDU partners. In relationships between seropositive IDU and non-IDU, consistent condom use was reported to be high (68%); this remained unchanged under multivariate controls. CONCLUSIONS: Self-reported condom use by IDU in New York, with its relatively mature epidemic, appears to be concentrated where it may most reduce the spread of HIV to non-IDU heterosexuals, i.e., in relationships between infected IDU and non-IDU partners. Differential condom use by serostatus and by partners' drug injection should be incorporated into mathematical models of the HIV epidemic. Causes of the high level of condom use in this subset of relationships may include drug injector altruism and pressure by sex partners; prevention programs should develop ways to use both of these factors to motivate increased condom use.