AMONG THE MOST serious health problems facing youth are drug use, 1,2 HIV, 3–6 and other sexually transmitted infections (STIs). 7,8 Sex risk behaviors such as engaging in sex with multiple partners and not using condoms consistently are common among U.S. youth 9 in colleges 10 and specific neighborhoods, including poor, minority, and urban neighborhoods in general 11,12 and Bushwick (the site of the current research) in particular. 12 Of the 18- to 24-year-olds in a national study, 85% had been sexually active in the preceding year, and 32% reported sex with multiple partners. 13 One important but relatively unstudied sex risk network characteristic is involvement with concurrent partners. This characteristic has implications for the spread of HIV 14 and other STIs. 15,16
Sex risk behaviors and networks, drug use, and STIs are interrelated. Alcohol and other drug use are related to less consistent condom use among young men, 17 and to a higher number of sex partners among both young men, 18,19 and young women. 20 Among 18- to 30-year-olds, findings show that alcohol and marijuana are related to a greater likelihood of sexual activity and sex with multiple partners, but not to consistent condom use. 18,21
Drug and sex behaviors are complex, and social researchers recently have begun to organize these behaviors into hierarchies. For example, for black and Puerto Rican adolescents in East Harlem, a stage measure of sex behavior (i.e., no involvement, deep kissing, petting, or sexual intercourse) was related to a stage model of drug usage (i.e., no drug use, alcohol or cigarette use only, use of marijuana but no other drugs, use of other illicit drug). 17
Crack use has been linked to high-risk sex among some but not all groups of youth. 22,23 Crack and other cocaine use, but not heroin or amphetamine use, were related to high-risk sex for women, but not for men, among patients at a sexually transmitted disease (STD) clinic. 24 Among black women, crack users had higher rates of high-risk sex behaviors than users of heroin. 25 Substance use, including use of crack and other cocaine, marijuana, and phencyclidine, is a risk factor for syphilis and other STIs. 26,27 Both injection drug and crack cocaine use are associated with HIV. 22,28
Relatively little is known about the relationships between the use of particular drugs and particular sex risk behaviors or network characteristics among young adults. One way of differentiating the use of different drugs is by determining the extent of stigma attached. In this study, we first examined how a drug’s location on a hierarchy of drugs (see the Methods section) is related to the particular sex risk network and behavior characteristics. We then examined relations between the use of particular drugs and the same sexual risk behaviors. Our population-based sample was taken in a section of New York City where the use of drugs, including crack and injected drugs, is common, 29,30 and where, among the thousands of local injection drug users in the early 1990s, 40% had HIV-positive test results and 70% had serologic evidence of exposure to hepatitis B. 31 Thus, we studied these relations in an environment with high potential consequences for sex risk networks and behavior characteristics.
Our first aim was to test the hypothesis that the use of drugs is associated with more risky sex, and that involvement in risky sex behavior and networks generally increases with position on a hierarchy of drugs. Our second aim was to explore the specific relations between the use of particular drugs and particular sex risk behaviors.
The data for this report come from a survey of 18- to 24-year-old youth in Bushwick, a low-income minority neighborhood in Brooklyn, New York, with a population of approximately 100,000. Drug use and drug selling are widespread in Bushwick, 29,30,32,33 as are some STIs, including herpes simplex virus type 2 and chlamydia among 18-to 21-year-olds. 12
We included two subsamples: a probability sample of household youth and a targeted sample of youth who used cocaine, heroin, crack, or injected drugs. This ensured sufficient users of these drugs for analysis (i.e., reasonable statistical power). Whereas the use of a probability sample has important advantages, the use of a targeted sample has significant advantages for studying rare, sensitive, or illegal behaviors. In our household sample, only 1.1% of the subjects had smoked crack in the preceding year, and less than 0.6% had injected drugs. Our combined sample contained 28 people who had injected drugs. Obtaining this number of injected drug users (IDUs) from a household sample would have required that it include approximately 5,000 people, which would have involved prohibitive expenditure in terms of both time and money. This combined sample was not representative of any general population, but only this type of sample would allow these relations to be understood. Furthermore, users of the most stigmatized drugs may have been underrepresented in a household sample 12
After their informed consent, the participants in this study were interviewed and offered a range of tests for STDs and HIV. They were assured that their responses and the results of all the tests would be confidential, except for the required reporting of active STDs according to public health regulations. The participants were paid $20 for completing the interview, and an additional $10 for giving blood and urine specimens.
Probability sampling of household youth was accomplished through a multistage sampling design. The first stage was the random selection of face-blocks. A face-block is defined as both sides of one street between adjacent city streets. At the beginning of the project (April, 1996), Bushwick had 577 face-blocks. The use of face-blocks instead of city blocks furthered the recruitment process via social interaction effects, allowing the field staff to establish themselves quickly as trustworthy people. Prior ethnographic research had shown that social interaction in Bushwick took place more often among neighbors on face-blocks (i.e., along and across a street) than with persons around the corner or across a back yard. 12 Face-blocks were screened sequentially after random ordering. One face-block could not be sampled because of intense hostility to the interviewers.
Young adults 18 to 24 years of age who had lived in a household at least 14 consecutive days before the screening were eligible for this study. Attempts were made to screen each dwelling unit. Screening was conducted mainly door-to-door. If the initial attempt failed to confirm the presence or absence of age-eligible residents, repeated attempts were made to screen each dwelling unit. Varied methods were used to determine the presence or absence of eligible persons in each dwelling unit. If more than one eligible person lived in a particular unit, one was randomly chosen. Extensive attempts were made to encourage the participation of selected individuals in the study. The 43 selected face-blocks contained 2,675 dwelling units, 2,404 (90%) of which were screened. Of the screened dwelling units, 499 (21%) had an eligible resident. Of these 499 eligible residents, 364 (73%) were interviewed. One resident who completed only part of the interview was not included in the results.
The targeted sample of young adults who had used heroin, cocaine, crack, or injected drugs in the preceding 6 months was recruited by a combination of ethnographically based targeted sampling in drug use venues and chain referral by household and targeted-sample participants. Age and residence eligibility were determined through at least one form of identification such as a driver’s license or school identification. In most cases, recent drug use status was confirmed through urine testing performed before the interview. When the urine test results for any eligible targeted sample participant were negative for heroin and cocaine metabolites, detailed oral screening before the interview was used to confirm that the participant had used at least one of these drugs in the preceding 6 months.
All the participants, whether recruited as part of the targeted sample or part of the household sample, were asked to recruit other 18- to 24-year-old Bushwick residents whom they had listed in their 12-month networks (defined later) as users of cocaine, heroin, crack, or any injected drugs. The received a $5 finder’s fee for each such eligible participant they recruited. Some respondents also functioned as auxiliary recruiters, recruiting age-eligible Bushwick residents who used heroin, cocaine, crack, or injected drugs, but who had not been listed originally in their 12-month network. Such use of chain referral may bias a sample in that more extroverted or popular people may have a greater likelihood of being nominated. 34 However, it is not possible to obtain a truly random sample of the drug user population, and others have used similar strategies to study such hidden populations. 35,36
Data were collected by structured interviews. The first interview was conducted in July 1997, and the last in June 2000. The interviews required 1.5 to 2.5 hours and were conducted either in our Bushwick storefront or in the respondents’ homes if privacy could be ensured. The main part of the questionnaire was administered by trained interviewers fully bilingual in Spanish and English. Most of the interviewers had extensive ties to the community.
The questionnaire focused on issues of drug use and its relation to behaviors and network characteristics that could put youth at risk for HIV or STDs. Relevant parts of the questionnaire included questions on the use of marijuana, cocaine, crack, heroin, and injected drugs in the preceding 12 months. There were questions on sex behaviors and networks. In addition, urinalysis for drug metabolites was performed before the interview. This may have had a “pipeline” effect, increasing the accuracy of self-reported drug use. 37
The dependent variables for this study were sex behaviors and sex network characteristics including number of sex partners, any unprotected sex, commercial sex work, concurrent partners, and partner sharing. Subjects were asked the number of people with whom they had engaged in sex (oral, vaginal, or anal) in the preceding 12 months. Commercial sex work was defined as sex for money, drugs, or other goods in the past 12 months. Unprotected sex was defined as vaginal sex without a condom at least once in the previous 12 months.
The interview included a network section in which the participants were asked about the behaviors of their current peers. First, they were asked to give the first names of the two friends with whom they felt closest. Next, they were asked to name up to three people who had engaged in sex with them in the past 12 months, up to two family members, and up to two people who in the preceding 12 months had used each of the following drugs: cocaine, heroin, crack, or injected drugs. Later, in the network section, the participants were asked additional questions about these people, regardless of the network(s) to which they belonged. That is, the same questions were asked about people from the peer, sex, drug use, and family networks, including whether the participant had ever engaged in sex with the network member.
This section of the interview was used to determine concurrency of sexual partnerships and sharing of sex partners. For each network member with whom they ever had sex, the participants were asked how many months ago they first and last had done so. Concurrency was defined as any overlapping partnerships in the preceding 12 months. Sharing of partners was defined as saying “yes” at least once when asked (for each network member) whether they had ever had sex with someone that the network member had also had sex with. Concurrency has been modeled in ways showing that it increases the spread of HIV in communities. Clearly, therefore, concurrency increases the probability that a person will be a “node” for through-transmission of the virus. 14 We created partner sharing as an alternative, innovative measure of network risk, one that is alter-focused rather than ego-focused. Both concurrency and partner sharing, therefore, may function as indicators of possible network risk and as crude indicators for the size and density of larger (sociometric) sex networks within a population.
The independent variable of main interest was illicit drug use, categorized as a six-level hierarchy showing the “hardest illicit drug used in the last 12 months”: none, marijuana, noninjected cocaine other than crack, noninjected heroin, crack, or IDU. This hierarchy was based primarily on the stigma attached to the various drugs. We initially hypothesized the existence of such a hierarchy, with assumptions drawn from the observation-based insights of our ethnographer about the stigma attached to the various drugs and from previous research indicating that drug use occurs in “stages.”38,39 Support for the hierarchy based on this data includes increased risk of HIV and other STIs at higher levels of the hierarchy 40 as well as an analysis confirming that peer norms on the drugs indicate increasing stigma at higher levels of the hierarchy. 41
First, we discuss the sample’s demographic and socioeconomic composition as well as the distribution of the dependent and independent variables. Second, we report on differences between men and women in terms of sex risk networks, behavior characteristics, and drug use. Third, we describe the relations between drug use and sex risk behaviors, with separate reports for men and women. Finally, we report on the differences in the relations by gender.
Of the 528 participants, 363 (69%) came from the household sample, 289 (55%) were male; 78% were Latino; 16% were black; 78% had never been married; 7% were legally married; and 11% were informally married or living together. Most (58%) had neither graduated from high school nor received a General Equivalency Diploma (GED). Of these, 27% currently were in school or a training program. Of those who either had graduated high school or had received a GED, 36% were in school or a training program. Slightly less than one third (31%) were currently employed. The median household income in the past year was $16,700. One fourth of the participants (141; 27%) had been incarcerated, 16% (82) in the past 12 months. The participants in the targeted sample were more likely than those in the household sample to be male (78% versus 44%;P < 0.001) or Latino (95% versus 78%;P < 0.01), and less likely to have graduated from high school or received a GED diploma (32% versus 47%;P < 0.001) or to be employed (20% versus 36%;P < 0.001). There were no significant differences between the two samples on marital status or household income.
Slightly more than one third (35%) of the participants had not used any illicit drug in the past 12 months. Of these, 136 (26%) had used only marijuana; 91 (17%) had used noninjected cocaine other than crack, but had not injected any drug or used heroin; 46 (9%) had used noninjected heroin, but had not injected any drug or smoked crack; 40 (8%) had smoked crack, but had not injected any drug; and 27 (5.4%) had used injected drugs.
Gender Differences in Drug Use Scale and Sex Risk
More men than women reported using stigmatized drugs (P < 0.01), according to the Jonckheere-Terpstra test of ordinal differences (Table 1). More specifically, the men were less likely to report no drug use and more likely to report use of noninjected cocaine other than crack or noninjected heroin. The men and women were about equally likely to report smoking marijuana, crack, or IDU.
The men were more likely to report concurrent partners in the past year and sharing of partners with at least one network member. The men also were more likely to report multiple partners during the past year. No significant differences were found between men and women in terms of engaging in unprotected sex or commercial sex work. The men also reported more noncommercial sex partners than did the women (Table 2). Although the women reported more commercial partners, this difference was not significant. The differences in concurrency, partner sharing, and multiple partners remained significant after controlling for commercial sex. The remaining analyses are reported separately for men and women.
Drug Use and Sex Risk by Gender
In general, both male and female respondents who were higher on the drug hierarchy had higher sex risk (Tables 3 and 4). They were more likely to have had concurrent partners, multiple partners, a history of commercial sex work, partners shared with a network member, and unprotected sex. The results in Tables 3 and 4 all remained significant when the analyses were performed only on sexually active participants and those who had not engaged in commercial sex, except that unprotected sex no longer was related significantly to drug use for women who were not sexually active.
There are different relations between particular drugs and particular sex risk behaviors and network characteristics for both men (Figure 1) and women (Figure 2). The interpretation of these results is limited because few people reported using drugs at the higher levels of the drug hierarchy.
Among the men, unprotected sex peaked with noninjected cocaine use, then leveled off, with similar proportions for drugs higher on the hierarchy. Partner sharing rose through noninjected cocaine use, then leveled off. Concurrent partnerships and multiple partnerships increased with hierarchical order of drug use (as discussed earlier), although the only significant single-step difference was between those who did not use drugs and marijuana users. Similarly, commercial sex work was more likely at higher-order drug use levels, although the only significant single-step difference was between marijuana users and users of noninjected cocaine other than crack. The mean number of sex partners was higher for drug injectors than for users in any other drug category (Table 4), and increased significantly with drug use category.
Among the women (Figure 2), unprotected sex showed little pattern beyond the slight but significant upward trend described in Table 3. Partner sharing showed a distinct upward trend, although the only significant single-step differences were between those who did not use drugs and marijuana users and between crack users and IDUs. Concurrency also showed a distinct upward trend, but the only significant single-step difference was between crack smokers and IDUs. Multiple partnerships increased strongly with drug use, showing two significant single-step differences: between those who did not use drugs and marijuana users, and between crack smokers and IDUs. Commercial sex work was quite rare among women who neither smoked crack nor injected drugs. A significant difference was found in commercial sex work between noninjected heroin users and crack smokers, and a further large, but nonsignificant, difference between crack smokers and IDUs. A small but significant difference also was found between nonusers and marijuana users. All 12 IDU women had multiple and concurrent partners.
Sex Differences in the Association of Drugs and Sex Risk
To determine whether the relations between drug use and sex risk were the same for the men and the women, we adjusted the relation between each sex risk and drug use for the mean of that sex risk for each gender (Figure 3A–E). For each sex risk, we subtracted the overall mean of the statistic for each gender from the level of that sex risk reported for subjects at each level of the drug hierarchy. For example, the first downward bar in Figure 3A (−0.22) indicates that the proportion of the non–drug-using men who had unprotected sex minus the proportion of all the men who had unprotected sex is −0.22. The relation between unprotected sex and drug use was shown to be similar in men and women. The other four sex risks, however, did show differences. In all four, the “effects” of IDU were greater for women than for men, and for commercial sex work, the effects of crack smoking also were greater for women. We are not aware of any statistical test of this difference with drug use treated as an ordinal variable.
To test for an interaction between gender and drug use level in predicting the various sex risks while drug use level is restricted to adjacent drugs on the hierarchy of stigma, we used logistic regression, which treats drug use as an interval scale. However, this led to many inestimable equations and small cell sizes. We also used logistic regression without restricting drug use level. Although the results must be viewed with caution because this analysis treats drug use as an interval scale, the findings do indicate significant interactions between drug use and gender in predicting the risk of multiple partnerships, commercial sex, and concurrent partnerships, and a nearly significant interaction in predicting partner sharing. As a precaution, we also ran these logistic regressions with several different scoring systems for level of drug use. This led to similar results, except that in some analyses, the interaction was a significant predictor of partner sharing.
The findings from this study are subject to several limitations. First, they are deliberately not statistically representative of young adults in Bushwick, inasmuch as a targeted sample of cocaine, crack, heroin, and injected drug users was included to provide needed analytic power.
Second, the degree of partner sharing and concurrency underestimates the true amount in the sample because we asked respondents to name only a maximum of three sex partners. However, this underestimate probably is not severe because 75% of the combined sample named two or fewer partners. For these people there was no underestimate, because of the questionnaire format. The underestimate may be less for the people who named users of cocaine, heroin, crack, or injected drugs as partners because people who named users of these substances also could name these users as sex partners. However, the difference in the underestimates probably is not large because even among those who did know substance users, 93% named three or fewer sex partners. Only 27 people named more than three sex partners. Restricting the analysis to the first three sex partners named did not alter any of the conclusions, nor did it substantially affect the results.
Third, we did not find any female IDUs in the household sample, which may reflect either an actual absence of female IDUs or differential reporting. The percentage of female IDUs who are commercial sex workers may have been overestimated because commercial sex workers are highly visible, and thus particularly likely to be recruited in a targeted sample.
Finally, this study involved a number of potentially confounding variables. One of the most important might have been that of having spent time in jail. A substantial proportion of our participants (15%) had spent time in jail during the preceding 12 months, and an even higher proportion of those reporting the use of hard drugs had jail experience. However, we reran the analyses, omitting those who had spent time in jail during the past 12 months, and all the significant results remained significant.
The general finding that young adult users of more stigmatized drugs engage in more sex risk confirms and extends earlier findings 18 in three ways. 17,19,20 First, this study showed that the relation of drug use to sex network and behavior risk holds for a sample that includes more users of highly stigmatized drugs (used with relative rarity) than previous studies.
Second, the relation holds for concurrency and partner sharing, which have not been extensively studied. It is important to note that concurrency and partner sharing measure characteristics of a person’s sex network, which transcend individual characteristics. Findings have shown network characteristics to be important in modeling the spread of HIV and STIs. 14–16,42–45
Third, the relation among young adults holds even for a neighborhood in which unprotected sex clearly poses a very high potential disease risk as a result of HIV and HBV reservoirs among IDUs 31 and high general rates of chlamydia, gonorrhea and herpes-2 among the youth. 12,32 This risk is exacerbated by the relation among hard drug use, incarceration, and infection with HIV and STIs. Hard drug users may function as a potential bridge group, transmitting infection from the prison system to the community 7,46
The greater range of drug use in the current sample than in previous research allows a more detailed look at the relations between the use of particular drugs and specific sex risks. This is important because it suggests more specific interventions. For example, the finding that commercial sex work is rare among women who sniff heroin or cocaine without injecting but more common among those who use crack or inject drugs suggests that interventions designed for commercial sex workers should target crack users and drug injectors rather than hard drug users in general. The greater range of drug use in this study also allowed us to examine the different relations between a range of drug use and sex risk for men and women.
The study of additional network and behavior risk variables also is important. The importance of concurrency in the spread of STDs is gaining recognition, 14–16 but has been relatively unstudied empirically, although findings occasionally have shown it to be associated with STDs. 47 To our knowledge, partner sharing has not been examined. However, it has clear implications for the spread of STDs.
Finally, studying the relation of drug use to sex network and behavior risk in the type of neighborhood targeted by the current investigation is important because such neighborhoods may be locations of endemic infection for HIV and other STDs. 48–52
These data may provide insight into community- and clinic-based observations that drug use is associated with STDs. 22,53–60 Specifically, they suggest several possible causal mechanisms. On the most general level, people who use more stigmatized drugs are more likely to engage in risky sex behaviors and to have multiple or concurrent partners, which lead in turn to increased rates of STDs. The large increase in sex risk behaviors and network characteristics for young women who either smoke crack or inject drugs, as compared with all others, suggests an additional possible causal mechanism: Women may engage in commercial sex to support their drug dependencies. This also would lead to an increase in the number of partners. It is important that this increase in sex network and behavior risk does not occur among female users of noninjected (noncrack) cocaine or noninjected heroin, particularly given the increases in noninjected heroin use in many cities in the United States 61,62 and around the world (see references cited in Neaigus et al 61).
It must be kept in mind that these data need not imply a direct link between the psychopharmacology of drugs and sex risk behaviors or networks. Other processes are likely, including economic pressure and social interaction, in which some people who engage in high-risk drug use also may gravitate toward high-risk sex, or vice versa.
Further research is needed to confirm and elaborate these causal mechanisms. More research also is needed to discover the links between particular drugs and particular sex and network risks. In particular, studies with larger samples of stigmatized drug users may further elucidate the nature of these links, especially the differences between men and women.
It should be noted also that there is an apparent dichotomy between those who use any drug (including marijuana) and those who use no drugs. Specifically, users of any drug are at substantially higher sex risk than those who use no drugs. In the current study, one reason for the number of significant differences between the marijuana users and those who used no drugs was sample size. Most of the participants were in one of these two groups. This does not account, however, for the size of the effects, which were substantial in most cases. In particular, the proportion of male marijuana users who had concurrent partners was more than double that for men who used no illicit drugs. For women, the proportion was nearly quadruple. Also, whereas less than half of the men who used no drugs had engaged in unprotected sex, nearly two thirds of the marijuana users had done so.
The findings presented in this report also have implications for intervention. One implication is that drug use prevention and treatment likely would reduce sex risk. This is so because young people who use drugs engage in more sex risk behaviors and are more likely to have concurrent or shared partners than those who do not use drugs. Also, among drug users, sex risk increases along a hierarchy of drugs. Drug use prevention programs also may involve change in sex risk networks.
Another implication is that interventions to reduce sex risk behaviors are needed among drug users. Harm reduction programs generally include efforts to encourage condom use and to help drug users stabilize both their general lives and their sex and drug behaviors. Because drug users, especially crack users and IDUs, are at higher risk for HIV and other STIs, 22,23,28 and because they engage in more risky sex with more partners than those who do not use drugs, they can play a key role in the transmission of infections. Therefore, any intervention that reduces their sex risk behaviors or the riskiness of their sex networks should have considerable impact. In particular, interventions that reduce the number of partners and the degree of concurrency should be effective in this regard. More concretely, at least for young adults, drug programs, even if not focused on IDUs, and harm reduction programs should teach safer sex techniques, distribute male and female condoms, and test for STIs.
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