Richard Curtis

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.

Syringe-mediated drug-sharing (backloading) : a new risk factor for HIV among injecting drug users

Background:In syringe-mediated drug-sharing (backloading), injecting drug users (IDU) use their syringes to mix drugs and to give measured shares to other IDU by squirting drug solution into the syringes of other IDU. Backloading has been discussed as a potential HIV risk factor, but its role as an HIV transmission route has not been established empirically. Methods:Six hundred and sixty IDU who had injected drugs in the previous 2 years were street-recruited from Bushwick, New York City through chain referral, tested for HIV antibody and interviewed about sexual and drug-risk behaviors. Results:Receiving drugs via backloading in the previous 2 years was reported by 24.5% of the subjects. These subjects had significantly higher HIV seroprevalence than those who did not receive drugs by backloading (odds ratio, 2.2; 95% confidence interval, 1.5–3.1). Backloading remained positively and significantly associated with HIV seropositivity in stepwise logistic regression, and in a series of simultaneous logistic models controlling for sociodemographic variables and for sexual and drug risk variables. Conclusions:Backloading can be a route of HIV transmission among IDU and should be incorporated into risk-factor studies and HIV transmission modeling. Many IDU who avoid other high-risk drug-injection practices may overlook the risk of backloading. HIV prevention programs should warn IDU against syringe-mediated drug-sharing and work together to develop ways to avoid it. AIDS 1993, 7:1653–1660

Syringe-mediated drug sharing among injecting drug users: Patterns, social context and implications for transmission of blood-borne pathogens

Drug injectors are at risk for infection with human immunodeficiency virus (HIV) and other blood-borne pathogens through the exchange of (infected) blood resulting from unhygienic injecting practices. Research attention and public discussion have focused primarily on the sharing of syringes and needles. While the focus on syringe sharing has sparked important interventions (bleach distribution, syringe exchange) it may have obscured the social relationship in which injecting equipment is used. Drug sharing plays a crucial role in the social organization of the drug using subculture. In this paper, various drug sharing practices and other distinguishable aspects of the injecting process-collectively termed Syringe-Mediated Drug Sharing (SMDS)-are described. All of these behaviors may put injecting drug users (IDUs) at risk for infection. The purpose of this paper is to stimulate scientific inquiry into SMDS behaviors and the social contexts which shape them. Descriptions are based primarily on field studies in Rotterdam and New York City. Recommendations for safer injecting training and education are proposed, as are directions for future research.

Risk networks and racial/ethnic differences in the prevalence of HIV infection among injection drug users

Studies among injection drug users (IDUs) find a higher prevalence of HIV infection among black and Puerto Rican IDUs than among white IDUs. Risk behaviors seldom explain these differences. We examine how risk networks contribute to racial/ethnic variations in HIV prevalence. Six hundred sixty-two IDUs were recruited on the street in Bushwick (New York City), interviewed, and tested for HIV. Risk behaviors and networks were analyzed to explain racial/ethnic variations in HIV. Forty percent of IDUs were infected with HIV. HIV prevalence was greater for Puerto Ricans (45%) and blacks (44%) than for whites (32%). Egocentric sexual and drug risk networks were predominantly racially/ethnically homogeneous. After multivariate adjustments for risk behaviors and risk networks, black-white differences in HIV prevalence were no longer significant. Although differences between Puerto Ricans and whites persisted, post hoc analyses suggested that network partner characteristics might explain these differences. In Bushwick, racially/ethnically discordant risk partnerships involving black IDUs may function as potential bridges of transmission between groups.

Street-level drug markets: Network structure and HIV risk

Abstract Ethnographic and formal social network methods are used to define and situate three categories of injecting drug users - a core, an inner periphery and an outer periphery - in a street-level drug market scene. Different locations in these network structures are shown to be associated with different levels of AIDS risk behaviors and of HIV infection rates. A network perspective helps to understand HIV risks and to devise appropriate interventions.

Stigmatized drug use, sexual partner concurrency, and other sex risk network and behavior characteristics of 18- to 24-year-old youth in a high-risk neighborhood.

Background Sex risks and drug use are related. This relation in youth is described. Goal To determine how stigmatized drug use is related to sexual risk behaviors and network characteristics among youth. Study Design In-person interviews were conducted with both a probability household sample (n = 363) and a targeted, street-recruited sample of cocaine, heroin, crack, or injected drug users (n - 165) comprising 18- to 24-year-olds in an inner city neighborhood. Drug use in the preceding 12 months was scaled hierarchically, lowest to highest social stigma, as none, marijuana, noninjected cocaine, noninjected heroin, crack, and injected drugs. Results Users of the more stigmatized drugs had more sex partners. They were more likely to report a history of concurrent sex partners, sex with someone who also had engaged in sex with a network member, commercial sex work, and unprotected sex. Findings showed crack use and drug injection to be associated more strongly with increased sex risk among women than among men. Conclusions Young users of the more stigmatized drugs are at much greater network and behavior risk for sexually transmitted diseases. Drug use prevention, harm reduction interventions, or both may lower this risk.

The Heroin Epidemic in New York City: Current Status and Prognoses

Since 1989, heroin production worldwide has risen; in New York City, as its purity rose and prices fell, street-level markets were restructured and offered heroin in addition to cocaine and crack (which had been popular during the 1980s). While officials estimate that there are between 500,000 and one million hard-core, chronic heroin users nationwide, evidence of supplemental users heralding another heroin era includes: more overdoses and overdose deaths, greater demand for treatment, larger seizures of heroin at all levels of distribution and related arrests, and broader media coverage. In this article, the authors describe the characteristics of populations in which there may have been a percentage increase of new users, such as young middle- or upper-class European-Americans, young Puerto Ricans and recent Haitian and Russian immigrants. The abstinence of young African-Americans is also noted. The article ends with a preliminary needs assessment of the new users in the areas of health (including AIDS), housing, employment, treatment, arrest and imprisonment.

Prevalence and correlates of anal sex with men among young adult women in an inner city minority neighborhood

In a population-representative sample of 202 18-24-year-old women in a neighborhood with widespread injection of drugs and HIV, 14% reported unprotected anal sex with men in the past year. Independent significant predictors were illegal drug use, having a main partner who takes the lead in deciding what to do during sex, and less self-deception. Having ever had anal sex was associated with having ever been infected with hepatitis B.

Sex, drugs, and infections among youth: Parenterally and sexually transmitted diseases in a high-risk neighborhood

Background and Objectives: To determine the extent to which youth who reside in households in a neighborhood with large numbers of drug injectors 1) are infected with parenterally or sexually transmitted agents, and 2) engage in high‐risk behaviors. Study Design: A multistage probability household sample survey was conducted in Bushwick, Brooklyn from 1994 to 1995. All households in 12 randomly selected primary sampling units were screened for age‐eligible youth. One hundred eleven English‐speaking 18‐ to 21‐year‐olds were interviewed. One hundred three sera were tested for human immunodeficiency virus type 1 (HIV‐1), hepatitis B virus, hepatitus C virus (HCV), human T‐cell lymphotrophic virus types I and II (HTLV‐I/II), herpes simplex virus type 2 (HSV‐2), or syphilis. Urines were tested for chlamydial infection, and for opiate and cocaine metabolites. Results: Eighty‐nine percent had sex in the past year, 45% with two or more partners. Only 19% of the sexually active always used condoms. Two (of 95) had had sex with a crack smoker. Thirty percent of women reported being coerced the first time they had sex, and 23% of women and 3% of men reported having been sexually abused. Only 3% reported ever using heroin, and 9% cocaine. Only one reported ever having injected drugs or smoked crack. Some underreporting of stigmatized behaviors occurred: two “nonreporters” had opiatepositive urines and two had cocaine‐positive urines. Marijuana use was common, with 48% using it in the past year. No subjects tested positive for HIV‐1, HTLV‐II, or syphilis; 2% tested positive for HTLV‐I and 3% for hepatitis C; 3% had hepatitis B markers, 12% had chlamydial infection, and 50% serologic HSV‐2 markers. Conclusions: Population‐representative samples of high‐risk communities can provide important knowledge. Although heroin and cocaine use, drug injection, and rates of infection with parenterally transmitted infectious agents appear to be lower among these youth, sexual risk behaviors and chlamydial and HSV‐2 infection are widespread. Sexually transmitted disease screening and outreach strategies are needed both to prevent sexually transmitted disease sequelae (including potential increased susceptibility to HIV infection) and to prevent transmission to partners.