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Biomedical subjects

Steffanie A Strathdee

Publications and source records attributed to Steffanie A Strathdee.

At least 55 records · Page 3Linked to original sources
PubMed2005

Behavioral risk exposure and host genetics of susceptibility to HIV-1 infection.

BACKGROUND: Some individuals are readily infected with low human immunodeficiency virus type 1 (HIV-1) exposure, whereas others appear less susceptible, suggesting that host genetics plays a role in the viral entry pathway. The matched case-control study design with measured risk exposures provides an avenue for discovering genes involved in susceptibility to infection. METHODS: We conducted a nested case-control study of African Americans (266 HIV-1 seroconverter cases and 532 seronegative controls from the AIDS Link to Intravenous Experience cohort), to examine the association between 50 single-nucleotide polymorphisms (SNPs) in 9 candidate genes (CCR5, CCR2, RANTES, MIP1A, MCP2, IL10, IFNG, MCSF, and IL2) and susceptibility to HIV-1 infection. To account for differential exposure propensities, risk behavior self-reported during semiannual visits was used to estimate a standardized cumulative risk exposure (SCRE). Individual SNPs were evaluated using conditional logistic-regression models, and the inferred haplotypes were assessed in the haplotype trend regression analyses after adjusting for age and SCRE. RESULTS: Four SNPs (CCR2-V64I, CCR5-2459, MIP1A+954, and IL2+3896) and specific haplotypes in the IL2 and CCR2/CCR5 regions were significantly associated with HIV-1 infection susceptibility in different genetic models. CONCLUSIONS: Our results suggest that genetic variants in associated host genes may play an important role in susceptibility to HIV-1 infection.

Adult↗
PubMed2005

Slower uptake of HIV antiretroviral therapy among Aboriginal injection drug users.

OBJECTIVES: We examined the time to antiretroviral therapy (ART) use among antiretroviral naïve HIV infected injection drug users participating in a prospective cohort study in Vancouver, Canada. METHODS: Time to the initiation of ART was evaluated using Kaplan-Meier methods and Cox proportional hazards regression. The cohort was stratified based on Aboriginal and non-Aboriginal (primarily Caucasian) ethnicity. RESULTS: Between May 1996 and May 2003, 312 HIV-infected individuals were enrolled into the cohort. At 24 months after enrollment, the rate of ART use was 29.2% among Aboriginal participants and was 53.7% among non-Aboriginal participants (log-rank P=0.023), and lower uptake of ART persisted in multivariate analyses (relative hazard = 0.37 [95% CI: 0.15-0.93]; P = 0.035). CONCLUSIONS: These findings demonstrate lower uptake of HIV/AIDS care among Aboriginal injection drug users and demonstrate the need for interventions to improve access to HIV care among indigenous populations.

Anti-Retroviral Agents↗
PubMed2005

Drug use and harm reduction in Afghanistan.

Opium has been cultivated in Afghanistan since 1100 A.D., although production has steadily increased since 1979. Currently, Afghanistan produces three-quarters of the global opium supply, with injection drug use and HIV currently following the opium trade route through Central Asia. Although systematic studies are lacking, heroin use appears to be on the rise in Afghanistan. The purpose of this paper is to briefly provide historical background and current statistics for drug production and use in Afghanistan, to discuss the new government's policies towards problem drug use and available rehabilitation programs, and to assess Afghan harm reduction needs with consideration of regional trends.

Journal Article↗
PubMed2005

High prevalence of alcohol use among hepatitis C virus antibody positive injection drug users in three US cities.

Injection drug users (IDUs) acquire the majority of new hepatitis C virus (HCV) infections and frequently use alcohol. Alcohol abuse accelerates liver disease among HCV-infected persons, can reduce the effectiveness of treatment for HCV infection and may be a contraindication for HCV treatment. HCV seropositive, HIV-negative IDUs aged 18-35 years in Baltimore, New York City and Seattle who were enrolled in a behavioral risk-reduction intervention trial underwent computerized self-interviews to assess baseline alcohol use and dependence and medical history. We measured problem alcohol use using the 10-item Alcohol Use Disorders Identification Test (AUDIT) scale. Of 598 participants, 84% responded "false" to: "it is safe for a person with HCV to drink alcohol". Problem drinking, defined as score > or =8 on AUDIT, was identified in 37%. Correlates of scoring > or =8 on AUDIT included homelessness, male gender, primarily injecting speedballs, having injected with used needles, prior alcohol treatment and depression. Although most HCV seropositive IDUs in our sample appear informed about their increased risk of liver disease from alcohol, two-fifths screened positive for problem alcohol use. These findings underscore the importance of referring HCV-positive persons to effective alcohol treatment programs to reduce future liver damage and improve eligibility for and effectiveness of treatment of HCV.

Adolescent↗
PubMed2005

Factors associated with interest in initiating treatment for hepatitis C Virus (HCV) infection among young HCV-infected injection drug users.

OBJECTIVE: We sought to identify factors associated with interest in receiving therapy for hepatitis C virus (HCV) infection among HCV-infected injection drug users (IDUs) in 3 United States cities. METHODS: IDUs aged 18-35 years who were HCV-infected and seronegative for human immunodeficiency virus underwent surveys on behaviors, experience, and interest in treatment for HCV infection and readiness to quit drug use. RESULTS: Among treatment-naive IDUs (n=216), 81.5% were interested in treatment for HCV infection, but only 27.3% had seen a health-care provider since receiving a diagnosis of HCV infection. Interest in treatment for HCV infection was greater among IDUs with a high perceived threat of progressive liver disease, those with a usual source of care, those without evidence of alcohol dependence, and those with higher readiness scores for quitting drug use. Interest in treatment for HCV infection was 7-fold higher among IDUs who were told by their health-care provider that they were at risk for cirrhosis or liver cancer. CONCLUSIONS: Improving provider-patient communication and integrating treatments for substance abuse and HCV may increase the proportion of IDUs who initiate treatment for HCV infection.

Adolescent↗
PubMed2005

Historical trends in the production and consumption of illicit drugs in Mexico: implications for the prevention of blood borne infections.

Mexico has cultivated opium poppy since before the 1900's and has been an important transit route for South American cocaine for decades. However, only recently has drug use, particularly injection drug use, been documented as an important problem. Heroin is the most common drug used by Mexican injection drug users (IDUs). Increased cultivation of opium poppy in some Mexican states, lower prices for black tar heroin and increased security at U.S.-Mexican border crossings may be contributing factors to heroin use, especially in border cities. Risky practices among IDUs, including needle sharing and shooting gallery attendance are common, whereas perceived risk for acquiring blood borne infections is low. Although reported AIDS cases attributed to IDU in Mexico have been low, data from sentinel populations, such as pregnant women in the Mexican-U.S. border city of Tijuana, suggest an increase in HIV prevalence associated with drug use. Given widespread risk behaviors and rising numbers of blood borne infections among IDUs in Mexican-U.S. border cities, there is an urgent need for increased disease surveillance and culturally appropriate interventions to prevent potential epidemics of blood borne infections. We review available literature on the history of opium production in Mexico, recent trends in drug use and its implications, and the Mexican response, with special emphasis on the border cities of Ciudad Juarez and Tijuana.

Coca↗
PubMed2005

The social structural production of HIV risk among injecting drug users.

There is increasing appreciation of the need to understand how social and structural factors shape HIV risk. Drawing on a review of recently published literature, we seek to describe the social structural production of HIV risk associated with injecting drug use. We adopt an inclusive definition of the HIV 'risk environment' as the space, whether social or physical, in which a variety of factors exogenous to the individual interact to increase vulnerability to HIV. We identify the following factors as critical in the social structural production of HIV risk associated with drug injecting: cross-border trade and transport links; population movement and mixing; urban or neighbourhood deprivation and disadvantage; specific injecting environments (including shooting galleries and prisons); the role of peer groups and social networks; the relevance of 'social capital' at the level of networks, communities and neighbourhoods; the role of macro-social change and political or economic transition; political, social and economic inequities in relation to ethnicity, gender and sexuality; the role of social stigma and discrimination in reproducing inequity and vulnerability; the role of policies, laws and policing; and the role of complex emergencies such as armed conflict and natural disasters. We argue that the HIV risk environment is a product of interplay in which social and structural factors intermingle but where political-economic factors may play a predominant role. We therefore emphasise that much of the most needed 'structural HIV prevention' is unavoidably political in that it calls for community actions and structural changes within a broad framework concerned to alleviate inequity in health, welfare and human rights.

Environment↗
PubMed2005

Circumstances surrounding the first injection experience and their association with future syringe sharing behaviors in young urban injection drug users.

Young injection drug users are at heightened risk for acquisition of blood-borne infections because of their high rates of unsafe injection behaviors, yet there has been little research examining the circumstances surrounding injection drug users' first injection experience ('hit'). We examined the relationship between factors associated with young drug users' first hit and their future syringe sharing behaviors among 420 new initiates to injection drug use (less than 5 years), aged 15-30 years old in urban Baltimore, Maryland. Contingency table analysis and logistic regression were used to determine the association between circumstances surrounding the first hit and recent receptive syringe sharing. Participants were primarily male (58.8%), White (71.2%), and were a median age of 24 years (interquartile range [IQR]: 21-27 years). Adjusting for race, gender, and homelessness, the following variables were independently associated with recent receptive syringe sharing: age at first hit (adjusted odds ratio [AOR] = 0.92 per year increase; 95% confidence interval [CI]: 0.87-0.98), self-injection at initiation (AOR = 0.55; 95% CI: 0.32-0.97) and using a syringe that had previously been used by someone else at first hit (AOR = 2.81; 95% CI: 1.70-4.64). These data suggest that injection-related risk behaviors may be established as early as the onset of injection initiation, supporting the need to educate non-injectors of the harms associated with unsafe injection practices.

Adolescent↗
PubMed2005

Methamphetamine-using HIV-positive men who have sex with men: correlates of polydrug use.

Methamphetamine use has become a major problem among communities of men having sex with men (MSM), where it has been associated with high-risk behaviors. Methamphetamine is often combined with other drugs that may increase its risks and adverse health consequences. To examine differences in background characteristics, HIVrisk behaviors, and psychosocial variables among polydrug-using HIV-positive MSM, the researchers classified a sample of 261 HIV-positive, methamphetamine-using MSM into three user groups: (1) methamphetamine only; (2) methamphetamine, marijuana, and poppers (light polydrug users); and (3) methamphetamine and other drugs (e.g., cocaine, heroin, hallucinogens, and ketamine; heavy polydrug users). Only 5% reported using only methamphetamine during the past 2 months; 31% were classified as light polydrug users, and 64% were classified as heavy polydrug users. Heavy polydrug users were significantly younger than light polydrug users (35.6 vs. 38.4, P<.01) and reported using methamphetamine for significantly fewer years (10.3 vs. 14.2 years, P<.001), but did not differ in the amount and frequency of methamphetamine or alcohol consumed. Heavy polydrug users reported significantly more sex partners of HIV-negative and unknown serostatus and had more unprotected sex with these partners. Heavy polydrug users had significantly higher scores on impulsivity and negative self-perceptions, as compared with those of light polydrug users. In this sample of HIV-positive MSM, most of those who used methamphetamine had a pattern of polydrug use. Heavy polydrug users reported significantly more high-risk sexual behaviors and tended toward higher levels of impulsivity than light polydrug users. The implications of these findings are two-fold: (1) Longitudinal research is needed to establish causal relationships among methamphetamine use, impulsivity, negative self-perceptions, and sexual risk behavior in this target population; (2) behavioral interventions should evaluate whether methamphetamine use and sexual risk behavior can be reduced by modifying impulsivity and negative self-perceptions.

Adult↗
PubMed2005

Sexual risk behavior among injection drug users before widespread availability of highly active antiretroviral therapy.

HIV testing and counseling has been associated with reductions in risk behaviors in some populations. This study examined whether involvement in a long-term study, including exposure to repeated HIV testing and counseling, was associated with increased condom use among injection drug users (IDUs) through a retrospective analysis of an IDU cohort from Baltimore, MD, during 1994-1998. Eligibility included being aged 18 years or older, injecting within 10 years and not having initiated antiretroviral therapy. A logistic model of high versus low risk, based on condom use, was used. Of 322 eligible IDUs, most were male (66%) and African-American (94%). No significant change in the odds of inconsistent condom use was observed with continued study exposure. Condom use remained low, indicating a need for interventions to reduce sexual risks and HIV transmission in this population.

AIDS Serodiagnosis↗
PubMed2005

Changes in willingness to participate in HIV vaccine trials among HIV-negative injection drug users.

Injection drug users (IDUs) represent an important risk group for HIV infection. We assessed correlates of IDUs' willingness to participate (WTP) in HIV vaccine trials, and examined temporal changes in WTP. Participants were enrolled in ALIVE, a prospective study of HIV among IDUs in Baltimore; semi-annual visits include interviews and HIV serology. Questionnaires regarding WTP were administered in 1993-1994 and again in 2001-2002. Logistic regression was conducted to identify correlates of WTP. Wave 1 of the survey included 440 participants; Wave 2 included 582 participants (189 participated in both waves). WTP increased modestly over time (83.4 vs. 86.3%; p = 0.16). Monetary incentives were the strongest predictor of WTP (adjOR = 2.73; 95% CI: 1.72-4.35). High expectations of HIV treatment effectiveness did not predict WTP. In this cohort, WTP remained strong and modestly increased over the study period. These results should be considered in the planning of sampling and retention strategies for future vaccine trials.

AIDS Serodiagnosis↗
PubMed2005

Theory and methodology for utilizing genes as biomarkers to determine potential biological mixtures.

PURPOSE: Genetically determined mixture information can be used as a surrogate for physical or behavioral characteristics in epidemiological studies examining research questions related to socially stigmatized behaviors and horizontally transmitted infections. A new measure, the probability of mixture discrimination (PMD), was developed to aid mixture analysis that estimates the ability to differentiate single from multiple genomes in biological mixtures. METHODS: Four autosomal short tandem repeats (STRs) were identified, genotyped and evaluated in African American, European American, Hispanic, and Chinese individuals to estimate PMD. Theoretical PMD frameworks were also developed for autosomal and sex-linked (X and Y) STR markers in potential male/male, male/female and female/female mixtures. RESULTS: Autosomal STRs genetically determine the presence of multiple genomes in mixture samples of unknown genders with more power than the apparently simpler X and Y chromosome STRs. Evaluation of four autosomal STR loci enables the detection of mixtures of DNA from multiple sources with above 99% probability in all four racial/ethnic populations. CONCLUSIONS: The genetic-based approach has applications in epidemiology that provide viable alternatives to survey-based study designs. The analysis of genes as biomarkers can be used as a gold standard for validating measurements from self-reported behaviors that tend to be sensitive or socially stigmatizing, such as those involving sex and drugs.

Black or African American↗
PubMed2005

Correlates of initiation of injection drug use among young drug users in Baltimore, Maryland: the need for early intervention.

This article examines individual and social factors associated with initiation of illicit drug injection, with a focus on racial differences. Data were derived from across-sectional survey of young injection and noninjection drug users in Baltimore, Maryland. Participants were aged 15 to 30 and had initiated use of heroin, cocaine, and/or crack within the prior five years. Bivariate and multivariate logistic regression models were used to identify correlates of injection initiation. Of 579 drug users, 73% were injectors, 56% were male, and 41% were African American. In a multivariate model controlling for age, correlates of injection initiation were: being an African American male [Adjusted Odds Ratio (AOR): 0.08; 95% Confidence Interval (CI): 0.04, 0.17] or female (AOR = 0.12; 95%CI: 0.06, 0.27) compared to being a White male; younger age of first use of alcohol, marijuana, or inhalants (AOR=0.73; 95%CI: 0.65, 0.82); shorter time between first use of alcohol, marijuana, or inhalants and first use of heroin, crack, or cocaine (per year decrease, AOR=0.63, 95%CI: 0.40, 0.87); parental drug use (AOR=0.54, 95%CI: 0.32, 0.92); seeing someone inject prior to injection, AOR=1.96, 95%CI: 1.01, 3.50); and crack smoking (AOR=1.77, 95%CI: 1.07, 2.99). Early drug use patterns and drug exposure factors are associated with initiation injection. Interventions are needed that target noninjection drug users to prevent transition to injection drug use.

Adolescent↗
PubMed2005

HIV prevalence and correlates of receptive needle sharing among injection drug users in the Mexican-U.s. border city of Tijuana.

Injection drug use is a growing but understudied problem in Tijuana, a city situated on the northwestern Mexico-U.S border. The authors studied factors associated with receptive needle sharing in an effort to inform prevention activities. In 2003, street-recruited injection drug users (IDUs) in Tijuana underwent interviews on injection risk behaviors and rapid HIV antibody tests. Logistic regression was used to identify correlates of receptive needle sharing at the last injection episode. Of 402 IDUs, 87.6% were male; the median age was 34. HIV prevalence was 4.01% (95% CI: 2.29-6.51). One third reported receptive needle sharing at last injection. Factors independently associated with receptive needle sharing were years living in Tijuana (Adjusted Odds Ratio [AdjOR]= 0.97 per year, 95% CI: 0.96-0.99), being bisexual/homosexual (AdjOR=2.12; 95% CI: 1.30 - 3.44), unemployed (AdjOR=2.5; 95% CI: 1.52-4.10), never having an HIV test (AOR: 4.02; 95% CI: 2.44-6.60), having friends who placed importance on avoiding HIV (AdjOR: 0.36; 95% CI: 0.19-0.68) and last injecting in a shooting gallery (AdjOR=1.98; 95% CI: 1.21-3.24). These results underscore the need to increase access to voluntary HIV testing and counseling to IDUs and migrants in Tijuana, as well as expand access to sterile syringes in an effort to avert widespread HIV transmission.

Adult↗
PubMed2005

Correlates of unsafe syringe acquisition and disposal among injection drug users in Baltimore, Maryland.

Because multi-person syringe use is the most common vehicle for HIV and hepatitis C virus transmission among injection drug users (IDUs), safe sources of sterile syringes and safe methods of disposal are necessary to curb these epidemics. We examined syringe acquisition and disposal in a cohort of IDUs in Baltimore. Between January 1, 1998 and December 31, 2001, 1034 participants reported on syringe acquisition at 3492 visits, and 953 reported on disposal at 2569 visits. Participants were 69.9% male, 93.9% African-American, and median age was 44. Syringes were acquired exclusively from unsafe sources at 32.3% of visits, while exclusively unsafe disposal was reported at 59.3% of visits. Significant correlates of unsafe acquisition were: attending shooting galleries, anonymous sex, sharing needles, smoking crack, and emergency room visits. Significant correlates of unsafe disposal were: injecting speedball, no methadone treatment, acquiring safely, and frequent injection. Having a primary source of medical care was associated with safe acquisition, but unsafe disposal. IDUs continue to acquire safely but dispose unsafely, especially among those with a primary source of care; this suggests that messages about safe disposal are not being disseminated as widely as those about acquisition. These data suggest the need for a more active program involving pharmacists, an expanded syringe access program, and better efforts to enhance safe disposal.

Adolescent↗
PubMed2005

Social contextual factors associated with entry into opiate agonist treatment among injection drug users.

We tested hypotheses that social living arrangement and drug use in one's network are independently associated with entry into opiate agonist treatment modalities. Injection drug users (IDUs) attending the Baltimore Needle Exchange Program who received a referral for drug abuse treatment were studied. Baseline interviews, HIV testing, and the Addiction Severity Index (ASI) were administered. Agency records were used to confirm entry into a treatment program offering opiate agonist maintenance therapy within 30 days of the baseline interview. Logistic regression was used to identify predictors of treatment entry. To date, of 245 IDUs, 39% entered such a program. Multivariate logistic regression models controlling for age and intervention status revealed that compared to individuals who lived alone, in a controlled, or nonstable environment (e.g., streets, abandoned house, transitional housing program, or boarding house), individuals who lived with a sexual partner were 3 times more likely to enter treatment (adjusted Odds Ratio [aOR]=3.04; p=0.013) and those who lived with family or friends were almost 3 times more likely to enter treatment (aOR=2.72; p=0.016). In the bivariate analyses, a marginal association was observed between being responsible for children or others and entry into treatment (p=0.066); however, this association was not significant in the multivariate model. Findings from this study suggest that supportive living environments may facilitate entry into treatment and may be helpful in devising appropriate and targeted interventions to encourage drug treatment entry.

Adult↗
PubMed2005

"Vivo para consumirla y la consumo para vivir" ["I live to inject and inject to live"]: high-risk injection behaviors in Tijuana, Mexico.

Injection drug use is a growing problem on the US-Mexico border, where Tijuana is situated. We studied the context of injection drug use among injection drug users (IDUs) in Tijuana to help guide future research and interventions. Guided in-depth interviews were conducted with 10 male and 10 female current IDUs in Tijuana. Topics included types of drug used, injection settings, access to sterile needles, and environmental influences. Interviews were taped, transcribed verbatim, and translated. Content analysis was conducted to identify themes. Of the 20 IDUs, median age and age at first injection were 30 and 18. Most reported injecting at least daily: heroin ("carga", "chiva", "negra"), methamphetamine ("crico", "cri-cri"), or both drugs combined. In sharp contrast to Western US cities, almost all regularly attended shooting galleries ("yongos" or "picaderos") because of the difficulties obtaining syringes and police oppression. Almost all shared needles/paraphernalia ["cuete" (syringe), "cacharros" (cookers), cotton from sweaters/socks (filters)]. Some reported obtaining syringes from the United States. Key themes included (1) pharmacies refusing to sell or charging higher prices to IDUs, (2) ample availability of used/rented syringes from "picaderos" (e.g., charging approximately 5 pesos or "10 drops" of drug), and (3) poor HIV/AIDS knowledge, such as beliefs that exposing syringes to air "kills germs." This qualitative study suggests that IDUs in Tijuana are at high risk of HIV and other blood-borne infections. Interventions are urgently needed to expand access to sterile injection equipment and offset the potential for a widespread HIV epidemic.

Adolescent↗