Injecting drugs in tight spaces: HIV, cocaine and collinearity in the Downtown Eastside, Vancouver, Canada

This commentary revisits the political turmoil and scientific controversy over epidemiological study findings linking high HIV seroincidence to syringe exchange attendance in Vancouver in the mid-1990s. The association was mobilized polemically by US politicians and hard-line drug warriors to attack needle exchange policies and funding. In turn, program restrictions limiting access to syringes at the Vancouver exchange may have interfaced with a complex conjunction of historical, geographic, political economic and cultural forces and physiological vulnerabilities to create an extraordinary HIV risk environment: (1) ghettoization of services for indigent populations in a rapidly gentrifying, post-industrial city; (2) rural-urban migration of vulnerable populations subject to historical colonization and current patterns of racism; and (3) the flooding of North America with inexpensive powder cocaine and heroin, and the popularity of crack. In fact, we will never know with certainty the precise cause for the extreme seroincidence rates in Vancouver in the early to mid-1990s. The tendency for modern social epidemiology to decontextualize research subjects and assign excessive importance to discrete, "magic bullet" variables resulted in a counterproductive scientific and political debate in the late 1990s that has obfuscated potentially useful practical lessons for organizing the logistics of harm reduction services - especially syringe exchange - to better serve the needs of vulnerable populations and to mitigate the effects of political-economically imposed HIV risk environments. We would benefit from humbly acknowledging the limits of public health science and learn to recognize the unintended consequences of well-intentioned interventions rather than sweep embarrassing histories under the rug.

The influence of needle exchange programs on injection risk behaviors and infection with hepatitis C virus among young injection drug users in select cities in the United States, 1994-2004

OBJECTIVE

Our purpose was to assess whether participation in needle exchange programs (NEPs) influenced incident hepatitis C virus (HCV) infection through effects on injection risk behaviors among young injection drug users (IDUs) in the United States.

METHODS

Data were drawn from three multi-site studies carried out in four major cities that enrolled IDUs over the period 1994-2004. Bivariate and multivariate analyses were conducted to assess relationships among sociodemographic characteristics, NEP use, injection risk behaviors, and prevalent or incident HCV infection.

RESULTS

Of the total participants (n=4663), HCV seroprevalence was 37%; among those who initially tested negative and completed follow-up at three, six, or 12 months (n=1288), 12% seroconverted. Nearly half of participants reported NEP (46%) use at baseline. Multivariate results showed no significant relationship between NEP use and HCV seroconversion. Controlling for sociodemographic characteristics, IDUs reporting NEP use were significantly less likely to share needles (aOR=0.77, 95% CI=0.67-0.88). Additionally, controlling for sociodemographic characteristics and program use, sharing needles, sharing other injection paraphernalia, longer injection duration, and injecting daily were all positively related to prevalent infection.

CONCLUSIONS

Our results suggest an indirect protective effect of NEP use on HCV infection by reducing risk behavior.

Needle Exchange and Injection-Related Risk Behaviors in Chicago

OBJECTIVE

To examine whether needle exchange program (NEP) use by injecting drug users (IDUs) affects injection risk behaviors over time.

METHODS

Between 1997 and 2000, 901 IDUs in Chicago were recruited for a cohort study from a multisite NEP and an area with no NEP. Participants were interviewed and tested for HIV at baseline and 3 annual follow-ups. Non-NEP users received HIV prevention services consistent with the Indigenous Leader Outreach Model. Random-effect logistic models were used to compare 5 injection-related risk behaviors between NEP users and nonusers.

RESULTS

The 30-day prevalence of receptive needle sharing decreased from 27.6% at baseline to 10.0% at visit 4 in NEP users and from 47.1% to 20.0% in nonusers. Similar patterns were observed for lending used needles, and NEP users were less likely to reuse their own needles. In multivariate analyses, NEP use was significantly associated with reduced odds of greater than 60% for receptive needle sharing, 45% for lending used needles, and 30% for sharing other injection paraphernalia as well as approximately a 2-fold increase in the odds of always bleaching used needles.

CONCLUSIONS

NEP use facilitates long-term reductions in injection risk practices, and the reductions are in addition to the effects of a behavioral intervention alone.

Paracetamol use and risk of ovarian cancer: a meta-analysis

AIM

Ovarian cancer remains the most fatal gynaecological malignancy. Several observational studies have examined paracetamol as a potential chemopreventive agent. The nonconclusive nature of the epidemiological evidence prompted us to conduct a detailed meta-analysis of the studies published on the subject in peer-reviewed literature.

METHODS

A comprehensive search for articles published up to 2004 was performed, reviews of each study were conducted and data were abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk estimates (RR) and 95% confidence intervals (CIs) were calculated using the random and the fixed-effects models.

RESULTS

Eight studies (four case-control and four cohort studies), published between 1998 and 2004, were included. We found no evidence of publication bias or heterogeneity among the studies. The analysis revealed an inverse association between paracetamol use and ovarian cancer risk. This association was marginally significant assuming a random-effects model (RR=0.84, 95% CI 0.70, 1.00), but not statistically significant assuming a fixed-effects model (RR=0.90, 95% CI 0.80, 1.01). When the analysis was stratified into subgroups according to study design, the association was inverse in both case-control and cohort studies, but only in the former was it statistically significant. The sensitivity analysis strengthened our confidence in the validity of this association. Furthermore, our results provided evidence for a dose effect; 'regular use' was associated with a statistically significant 30% reduction in the risk of developing ovarian cancer compared with non-use (RR=0.70, 95% CI 0.51, 0.95).

CONCLUSIONS

Our meta-analysis supports a protective association between paracetamol use and ovarian cancer, and provides evidence for a dose effect. However, the question of paracetamol's potential association with ovarian cancer deserves further verification, since proof of chemoprevention would represent a major public health advance.

HIV/hepatitis C virus co-infection in drug users: risk behavior and prevention

Studies of HIV-positive patients have consistently shown that drug users, in particular injection drug users (IDU), are far more likely to have hepatitis C virus (HCV) infection than other patient groups. HIV incidence and prevalence in IDU has declined in recent years, but HCV remains endemic in this population. HCV antibody prevalence among non-injection users of drugs such as heroin and cocaine is between 5 and 30%, although there are scant data on specific transmission risk behavior. The control of HIV/HCV co-infection must address HCV prevention. Epidemiological studies have suggested that HCV prevalence in IDU is subject to various influences, some of which may be modifiable by interventions. However, studies have not shown consistent effects of various prevention strategies on HCV transmission, including studies of HCV screening and education, drug treatment or needle exchange. Although some large cross-sectional studies in regions where needle exchange is available to a large number of drug injectors have reported declining HCV prevalence, the scale of services needed is a matter of considerable debate and has not been systematically quantified. Priorities for research related to the prevention of HIV/HCV co-infection should include estimating the effect on disease occurrence of eliminating specific risk factors, and specifying the level of resources needed to alter HCV incidence.

HIV Risk Practices Among Needle Exchange Users and Nonusers in Chicago

OBJECTIVES

To assess associations between needle exchange program (NEP) use and drug injection risk practices.

METHODS

Between 1997-2000, injecting drug users (IDUs) in Chicago were recruited from NEPs and an area with no NEP, interviewed about risk practices, and counseled and tested for HIV. The risk practices of "regular NEP users"--those who obtained at least half of their needles from an NEP (n = 558)--were compared with those of IDUs who did not use an NEP (n = 175).

RESULTS

In multivariate analysis, regular NEP users, compared with NEP nonusers, were less likely to receptively share needles (adjusted odds ratio [AOR], 0.30; 95% CI, 0.19-0.46); lend used needles (AOR, 0.47; 95% CI, 0.31-0.71); share cookers (AOR, 0.39; 95% CI, 0.25-0.61), cottons (AOR, 0.48; 95% CI, 0.32-0.72), or water (AOR, 0.41; 95% CI, 0.27-0.63); or use a needle for >1 injection (0.15; 95% CI, 0.08-0.27). Among those who shared needles, regular NEP users were significantly more likely to do so for a smaller proportion of injections, with fewer partners and persons socially closer, and to have always bleached used needles before injecting.

CONCLUSIONS

Regular NEP use is associated with less frequent and lower risk HIV injection risk practices.

The effect of syringe exchange use on high-risk injection drug users: a cohort study

OBJECTIVE

To determine whether syringe exchange program use is associated with cessation of syringe sharing among high-risk injection drug users.

DESIGN AND METHODS

Between 1992 and 1996, street-recruited injection drug users were interviewed and received HIV testing and counseling semi-annually, as part of a dynamic cohort study. We examined a cohort of 340 high-risk injection drug users for whom two observations, 6-months apart, were available and who reported syringe sharing at the first interview. Multivariate logistic regression analysis was performed to determine the relationship between syringe exchange program use and cessation of syringe sharing, while controlling for confounding factors.

RESULTS

At follow-up interview, 60% (204 of 340) reported quitting syringe sharing. High-risk injection drug users who began using the syringe exchange program were more likely to quit sharing syringes [adjusted odds ratio (AOR), 2.68; 95% confidence interval (CI), 1.35-5.33], as were those who continued using the syringe exchange program (AOR,1.98; 95% CI, 1.05-3.75) in comparison with non-syringe exchange program users, while controlling for confounding factors.

CONCLUSIONS

The initiation and continuation of syringe exchange program use among high-risk injection drug users is independently associated with cessation of syringe sharing. Syringe exchange program use can be an important component in reducing the spread of blood-borne infectious diseases among high-risk injection drug users.