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Biomedical subjects

D Vlahov

Publications and source records attributed to D Vlahov.

At least 55 records · Page 3Linked to original sources
PubMed2001

Prevalence, incidence, and correlates of chlamydia and gonorrhea among young adult injection drug users.

PURPOSE: To measure prevalence, incidence, and correlates of chlamydia and gonorrhea among injection drug users (IDUs). METHODS: Participants (n = 2129; 63% male, 52% white, ages 18-30 years) in five US cities were tested for chlamydia and gonorrhea by urine LCR assay and completed a standardized questionnaire about demographics and recent sexual behavior. Logistic regression identified correlates of prevalent infection; incidence rates were calculated from 6-month follow-up data. RESULTS: Chlamydia prevalence was 5.2% and did not differ by gender. Gonorrhea prevalence was 0.2% among men and 2.0% among women, P < .001. Among men, younger age [OR (95% CI): 0.89 (0.83-0.96)], age at sexual debut [0.91 (0.83-0.99)], and African American race [2.92 (1.53-5.59)] were associated with chlamydia. Among women, age at sexual debut [1.16 (1.02-1.31)] and commercial sex [1.96 (1.03-3.74)] were associated with chlamydia, and with gonorrhea [1.27 (1.04-1.56)] and [5.17 (1.66-16.11)], respectively. At 6 months, the cumulative incidence of chlamydia was 1.7% among men and 4.4% among women, P = .03; no men and 1.3% of women tested positive for gonorrhea, P = .01. IMPLICATIONS: Prevalence and correlates of chlamydia and gonorrhea were similar to other samples, suggesting that screening criteria need not be modified for IDU populations. The number of behavioral correlates identified was limited; perhaps unmeasured sexual-network-level factors play a role in determining sexually transmitted disease (STD) prevalence.

Adolescent↗
PubMed2001

Health care utilization among young adult injection drug users in Harlem, New York.

PURPOSE: This cross-sectional study investigated the predictors for and patterns of health care utilization among young adult injection drug users (IDUs). METHODS: The subjects were 206 IDUs, ages 18-29, who were street-recruited from Harlem, New York. Participants were interviewed about their drug use, health conditions, and use of services such as health care, needle exchange programs (NEPs), and drug treatment in the preceding 6 months. Data were analyzed using logistic regression. RESULTS: Health insurance was associated with use of health care both among NEP users [AOR (adjusted odds ratio) 10.66] and non-NEP users (AOR 2.45). Use of health care was independently associated with drug treatment (AOR 2.58), being gay/bisexual (AOR 3.86), and negatively associated with injecting cocaine (AOR 0.56). Half the participants (49%) had used health care in the previous 6 months; 48% were uninsured. Many participants who did not use health services reported a condition that would have warranted medical care. IMPLICATIONS: Health insurance was strongly associated with use of health care, particularly among those who attend NEPs. Young adult IDUs may benefit from increased efforts to help them arrange and maintain health insurance coverage, potentially at NEPs. NEPs may be connecting young IDUs with health insurance to medical care through referrals.

Adolescent↗
PubMed2001

Injecting misuse of buprenorphine among French drug users.

AIMS: To evaluate the extent to which the introduction (February 1996) of ambulatory prescriptions of buprenorphine for drug maintenance treatment (DMT) has been associated with its intravenous illicit use by French injecting drug users (IDUs). DESIGN: Cross-sectional survey (September 1997), using self-administered questionnaires, in a sample of IDUs recruited at 32 pharmacies, four needle exchange programmes and three syringe vending machines. SETTING: Thirty-nine sites where IDUs have access to sterile syringes in the city of Marseille (South-Eastern France). PARTICIPANTS: Sample of IDUs attending community pharmacies, vending machines and needle exchange programs to obtain equipment. MEASUREMENT: To compare characteristics of IDUs who declared that they only injected buprenorphine in the prior 6 months versus the rest of the sample. FINDINGS: Among the 343 respondents (response rate = 70.7%), 33.8% were polydrug users who occasionally injected buprenorphine in parallel to heroin and/or cocaine, while 23.9% only injected buprenorphine in the previous 6 months. IDUs in this latter group were younger, injected more frequently, and were more frequently on buprenorphine DMT, but they were less likely to be HIV-infected and to declare HIV-related injecting risky behaviours. CONCLUSIONS: Substantial risk of injecting misuse is associated with large-scale diffusion of buprenorphine DMT. A more stringent regulation for medical dispensation of buprenorphine than the current French general freedom of prescription for all physicians, including general practiioners in ambulatory care, may be necessary in other countries which are considering the diffusion of buprenorphine DMT.

Adolescent↗
PubMed2001

Highly active antiretroviral therapy associated with improved anemia among HIV-infected women.

Anemia is common during human immunodeficiency virus (HIV) infection and is associated with increased mortality. We conducted a study to examine the impact of highly active antiretroviral therapy (HAART) on anemia in a multicenter cohort of HIV-positive women, the Human Immunodeficiency Virus Epidemiology Research (HER) Study. Among women receiving HAART (n = 188), non-HAART monotherapy or combination antiretroviral therapy (ART) (n = 111), or who had no reported treatment (n = 62), the prevalence of anemia (hemoglobin, <120 g/L) at baseline was 38.3, 36.9, and 43.6%, respectively (p = 0.58) and at 1-year follow-up was 26.1%, 36.9%, 45.2%, respectively (p = 0.01); mean hemoglobin at baseline was 125 +/- 16, 122 +/- 16, and 122 +/- 18 g/L, respectively (p = 0.29) and at 1-year follow-up was 128 +/- 14, 123 +/- 16, and 119 +/- 20 g/L, respectively (p < 0.0001). Adjusted linear regression models showed that HAART was associated with an increase of hemoglobin of 0.20 g/L per month (p = 0.007). After 1 year of treatment, HAART was associated with a 32% reduction in anemia among HIV-infected women (p = 0.01), whereas there was no significant change in the prevalence of anemia among those on non-HAART ART or those who had no reported treatment. HAART is associated with a large reduction in anemia among HIV-infected women.

Adult↗
PubMed2001

Sexual orientation and HIV infection prevalence among young Latino injection drug users in Harlem.

Among injection drug users (IDUs), those at highest risk for HIV infection include Latinos, young women, and young men who have sex with men (homosexual men). We examined how HIV infection prevalence is affected by gender and sexual orientation among young Latino IDUs in New York City. We used baseline data from a cohort study of young (18-30 years) IDUs in Harlem, New York City, conducted from 1997 through 1999. Participants were asked about drug use and sexual behaviors, and blood was taken for HIV, hepatitis B, and hepatitis C viral antibody testing. Of 156 participants who self-identified as Latino, 145 (94%) were Puerto Rican. Overall, 101 (65%) were heterosexual men, 11 (7%) were men who have sex with men (MSM), 32 (20%) were heterosexual women, and 12 (8%) were women who have sex with women (WSW). Of the whole cohort, 17 (11%) were HIV positive. HIV infection rates were higher among WSW (42%, p < 0.05), heterosexual women (16%, p < 0.05), and homosexual men (18%, p = 0.09) than heterosexual men (5%). Compared with heterosexual men, homosexual men were significantly (p < 0.05) more likely to have received money or drugs for sex (64% versus 33%), and WSW were significantly more likely to have had unprotected sex with an IDU 5 years or more older (50% versus 16%). Multivariate analysis showed being a WSW (adjusted odds ratio [AOR] = 8.68, 95% confidence interval [CI] 1.78-42.26) and having unprotected sex with an older IDU (AOR = 7.01, 95% CI 2.23-21.96) to be associated with HIV infection. Sexual transmission may account for many HIV infections among young Latino IDUs. The high prevalence of HIV infection among WSW may, in part, be due to their having unprotected sex with older men, but studies with larger sample sizes are needed to confirm this.

Adolescent↗
PubMed2001

Needle-exchange participation, effectiveness, and policy: syringe relay, gender, and the paradox of public health.

Needle-exchange programs (NEPs) have been politically controversial, and most studies have focused on evaluating their effectiveness on human immunodeficiency virus (HIV) transmission rates with little emphasis on the process of how they are used. This article shows that the way intravenous drug users use NEPs may influence their effectiveness. Using data from Baltimore's NEP, participants (N = 2,574) were classified as low, medium, and high users based on the volume, frequency, and duration of contact with the NEP. Higher NEP use was associated with shorter syringe circulation times and less syringe relay, returning syringes to the NEP originally acquired by someone else. For a subsample that was HIV tested (N = 262), syringe relay among women was associated with HIV seroconversion (at a 95% confidence interval). We conclude that exclusive use of the NEP (no relay) provides greater HIV protection than NEP use involving syringe relay. The paradox is that public health goals will not be achieved by prohibiting syringe relay activities and promoting exclusive use. NEPs should broaden their education efforts to have participants understand the value of repeated visits to the NEP.

Adult↗
PubMed2001

Factors associated with adolescent initiation of injection drug use.

OBJECTIVE: The purpose of this study was to evaluate the extent to which demographic, sexual, and non-injection drug use practices predict adolescent initiation of injection drug use. METHODS: Street recruited injection drug users 15-30 years of age in Baltimore, Maryland, who initiated injection within five years of study enrollment, completed a questionnaire that included a year-by-year history regarding the five years prior to initiation of injection. Factors associated with initiation during adolescence (< or = 21 years of age) versus young adulthood (>21 ) were determined using logistic regression. RESULTS: Of 226 participants, most were female (61%) and African American (64%). Median age of participants was 25; median age at initiation of injection was 23. Factors significantly associated with adolescent initiation in multivariate analysis included race other than African American, and practices prior to initiating injection including condom use, lack of cocaine use, exclusive crack smoking just prior to initiation, and smoking marijuana. Adolescent initiates also had shorter durations of illicit drug use prior to initiating injection. CONCLUSION: Short-term non-injection drug use, particularly exclusive crack smoking, was associated with adolescent initiation of injection drug use. Early prevention efforts targeting this high-risk group of younger drug users are warranted in order to delay or prevent onset of injection drug use.

Adolescent↗
PubMed2001

Human immunodeficiency virus seroconversion and evolution of the hepatitis C virus quasispecies.

When chronic hepatitis C virus (HCV) infections are complicated by acquisition of human immunodeficiency virus (HIV), liver disease appears to accelerate and serum levels of HCV RNA may rise. We hypothesized that HIV might affect the HCV quasispecies by decreasing both complexity (if HIV-induced immunosuppression lessens pressure for selecting HCV substitutions) and the ratio of nonsynonymous (d(N)) to synonymous (d(S)) substitutions, because d(N) may be lower (if there is less selective pressure). To test this hypothesis, we studied the evolution of HCV sequences in 10 persons with chronic HCV infection who seroconverted to HIV and, over the next 3 years, had slow or rapid progression of HIV-associated disease. From each subject, four serum specimens were selected with reference to HIV seroconversion: (i) more than 2 years prior, (ii) less than 2 years prior, (iii) less than 2 years after, and (iv) more than 2 years after. The HCV quasispecies in these specimens was characterized by generating clones containing 1 kb of cDNA that spanned the E1 gene and the E2 hypervariable region 1 (HVR1), followed by analysis of clonal frequencies (via electrophoretic migration) and nucleotide sequences. We examined 1,320 cDNA clones (33 per time point) and 287 sequences (median of 7 per time point). We observed a trend toward lower d(N)/d(S) after HIV seroconversion in 7 of 10 subjects and lower d(N)/d(S) in those with rapid HIV disease progression. However, the magnitude of these differences was small. These results are consistent with the hypothesis that HIV infection alters the HCV quasispecies, but the number of subjects and observation time may be too low to characterize the full effect.

Adult↗
PubMed2001

Multiple access to sterile syringes for injection drug users: vending machines, needle exchange programs and legal pharmacy sales in Marseille, France.

OBJECTIVE: In Marseille, southeastern France, HIV prevention programs for injection drug users (IDUs) simultaneously include access to sterile syringes through needle exchange programs (NEPs), legal pharmacy sales and, since 1996, vending machines that mechanically exchange new syringes for used ones. The purpose of this study was to compare the characteristics of IDUs according to the site where they last obtained new syringes. METHODS: During 3 days in September 1997, all IDUs who obtained syringes from 32 pharmacies, four NEPs and three vending machines were offered the opportunity to complete a self-administered questionnaire on demographics, drug use characteristics and program utilization. RESULTS: Of 485 individuals approached, the number who completed the questionnaire was 141 in pharmacies, 114 in NEPs and 88 at vending machines (response rate = 70.7%). Compared to NEP users, vending machine users were younger and less likely to be enrolled in a methadone program or to report being HIV infected, but more likely to misuse buprenorphine. They also had lower financial resources and were less likely to be heroin injectors than both pharmacy and NEP users. CONCLUSIONS: Our results suggest that vending machines attract a very different group of IDUs than NEPs, and that both programs are useful adjuncts to legal pharmacy sales for covering the needs of IDUs for sterile syringes in a single city. Assessment of the effectiveness and cost-effectiveness of combining such programs for the prevention of HIV and other infectious diseases among IDUs requires further comparative research.

Adolescent↗
PubMed2001

Factors associated with prevalent hepatitis C: differences among young adult injection drug users in lower and upper Manhattan, New York City.

OBJECTIVES: This study examined correlates of prevalent hepatitis C virus (HCV) infection among young adult injection drug users in 2 neighborhoods in New York City. METHODS: Injection drug users aged 18 to 29 years were street recruited from the Lower East Side and Harlem. Participants were interviewed about drug use and sex practices; venipuncture was performed for hepatitis B virus (HBV), HCV, and HIV serologies. RESULTS: In both sites, testing positive for HCV antibody (anti-HCV) was associated with having injected for more than 3 years. Additionally, HCV infection was positively associated with injecting with someone known to have had hepatitis (but the association was significant only in the Lower East Side) and with sharing cotton (but the association was statistically significant only in Harlem). Being in drug treatment and older than 24 years were associated with HCV in the Lower East Side but not in Harlem. Receiving money for sex was associated with anti-HCV positivity in Harlem but not in the Lower East Side. CONCLUSIONS: Several differences in factors associated with prevalent HCV infection existed among 2 populations of young injection drug users from the same city. Indirect transmission of HCV may occur.

Adolescent↗
PubMed2001

Selective risk taking among needle exchange participants: implications for supplemental interventions.

OBJECTIVES: This study characterized social network context of HIV risk behavior among injection drug users who participated in a needle exchange program. METHODS: Interviews were conducted with 1184 injection drug users at the Baltimore Needle Exchange Program enrolled in an evaluation cohort. Analysis consisted of multiple logistic regression with statistical adjustment for the interdependence of observations. RESULTS: Of the 203 (17.1%) injection drug users who reported using a syringe after someone else, 78.3% reported sharing with close friends, and the adjusted odds ratio of any sharing and sharing with close friends was 30.9. Injection drug users were more likely to report sharing with a strong-tie close friend (adjusted odds ratio = 1.52) and less likely to report sharing with other close friends if those friends were weak ties and new to their network. Friendship ties were not stable, with fewer than 30% of the friends being repeat nominations. CONCLUSIONS: These data show that many injection drug users engage in selective risk taking that may minimize their disease risk exposure in the short term. The turnover in networks, however, suggests that programs need to emphasize the importance of exclusive use.

Adult↗
PubMed2001

Evidence of rodent-associated Bartonella and Rickettsia infections among intravenous drug users from Central and East Harlem, New York City.

We tested serum samples collected in 1997 and 1998 from a cohort of 204 injection drug users (IDUs) recruited from Central and East Harlem, New York City, New York, for antibodies reactive with seven rickettsial or Bartonella spp. antigens. Rodent-associated Bartonella elizabethae and Rickettsia akari were the primary etiologic agents of interest. The testing panel also included Bartonella henselae, Bartonella quintana, Rickettsia prowazekii, Rickettsia rickettsii, and Rickettsia typhi. The highest prevalence of seroreactive serum samples (46%) was found with B. elizabethae antigens; 10% of the samples reacted with B. henselae antigens, while 2% reacted with B. quintana antigens. Reactivity to the latter two antigens was likely due to cross-reactivity with B. elizabethae antigens in most instances. Among the spotted fever group rickettsiae, 18 (9%) samples reacted with R. akari, including 10 samples (5%) that also reacted with R. rickettsii. Cross-adsorption studies demonstrated that most of the spotted fever group rickettsiae antibodies were due to R. akari infections. Among the typhus group rickettsiae, 5 samples reacted weakly to R. prowazekii antigens, and no samples reacted with R. typhi antigens. These findings suggest that Harlem IDUs are commonly exposed to two rodent-associated zoonotic agents. Further study of IDU populations may help elucidate transmission cycles of these agents in inner cities where higher levels of transmission occur.

Adolescent↗
PubMed2000

Genetic restriction of HIV-1 pathogenesis to AIDS by promoter alleles of IL10.

IL10 is a powerful TH-2 cell cytokine produced by lymphoid cells that limits HIV-1 replication in vivo, ostensibly by inhibiting macrophage/monocyte and T-cell lymphocyte replication and secretion of inflammatory cytokines (IL1, TNFalpha, IL6, IL8, and IL12). A genetic epidemiological scan of patients enrolled in AIDS cohorts for candidate gene-linked short tandem repeat polymorphisms revealed significant genotype associations for HIV-1 infection and progression to AIDS with markers adjacent to and tracking (by linkage disequilibrium) common single nucleotide polymorphic variants in the IL10 promoter region. Individuals carrying the IL10-5'-592A (IL10-5'A) promoter allele possibly were at increased risk for HIV-1 infection, and once infected they progressed to AIDS more rapidly than homozygotes for the alternative IL10-5'-592 C/C (IL10-+/+) genotype, particularly in the later stages of HIV-1 infection. An estimated 25-30% of long-term nonprogressors (who avoid clinical AIDS for 10 or more years after HIV-1 infection) can be attributed to their IL10-+/+ promoter genotype. Alternative IL10 promoter alleles are functionally distinct in relative IL10 production, in retention of an avian erythroblastosis virus transcription factor recognition sequence and in binding to specific putative nuclear transcription factors, suggesting a potential mechanism whereby IL10-5'A down-regulation of inhibitory IL10 facilitates HIV-1 replication in vivo, accelerating the onset of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Influence of CCR5 promoter haplotypes on AIDS progression in African-Americans.

OBJECTIVES: To test the hypothesis that the CCR5 promoter variants in HIV-1-infected African-Americans affect the rate of progression to AIDS and to determine the extent of linkage disequilibrium between the CCR5P1 allele and the CCR5 59029A variant (referred to here as CCR5-2459A), both of which have been shown independently to accelerate AIDS progression in Caucasians. DESIGN: We used survival analysis to assess the effects of CCR5 promoter variants in HIV-1 seroincident Caucasians and African-Americans. SUBJECTS AND METHODS: Genotypes were determined for 806 Caucasians and 1067 African-Americans, which included 700 seroconverters, enrolled in four HIV/AIDS natural history cohort studies. These genotypes were used to determine linkage and haplotypes for CCR2 and CCR5 alleles. Survival analysis was used to assess the effect of CCR2, CCR5, and CCR5 promoter haplotypes on progression to AIDS in seroincident African-Americans. RESULTS: A survey of Caucasians and African-Americans demonstrated complete linkage disequilibrium between CCR5P1 and CCR5-2459A sites. The composite CCR5P1 haplotype (including the CCR5-2459A allele) is shown to be associated with rapid progression to AIDS endpoints in both African-American and Caucasian cohorts, but the effect is recessive in Caucasians and dominant in African-Americans. This is probably due to the presence of modulating genes or as yet unidentified polymorphisms that may differ between racial groups.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Correlates of enrollment in methadone maintenance treatment programs differ by HIV-serostatus.

OBJECTIVES: To identify correlates of enrollment in methadone maintenance treatment programs (MMTP) among a prospective cohort of injection drug users (IDUs) in Baltimore, Maryland. METHODS: A total of 1480 IDUs undergoing semi-annual HIV tests and interviews were studied between 1994 and 1998, during which time a needle exchange program was introduced. Longitudinal analysis using generalized estimating equations was used to identify correlates of MMTP participation over time. RESULTS: Although similar proportions of HIV-seropositive and -seronegative IDUs enrolled in MMTP during follow-up (26 versus 22%, respectively), correlates of enrollment differed by HIV-serostatus. Among HIV-seropositive participants, older age [adjusted odds ratio (AOR, 1.37)] was associated with enrollment in MMTP. Among HIV-seronegative IDUs, factors associated with not enrolling in MMTP were being African American (AOR, 0.22) and having been recently incarcerated (AOR, 0.62) or homeless (AOR, 0.72). In both groups, females were twice as likely to be enrolled in MMTP, and those with Medicaid were 1.5 times more likely to be enrolled. When behavioral factors were lagged one visit, needle exchange program attendance was positively associated with MMTP enrollment among HIV-negative IDUs (AOR, 2.10); however, this association diminished significantly over time as dedicated treatment slots for needle exchange program participants became saturated. CONCLUSIONS: These findings underscore the need to improve access to MMTP, especially to certain subgroups such as African-Americans, the homeless, incarcerated and uninsured. Our data suggest that health care providers and needle exchange programs can facilitate enrollment into MMTP provided that adequate treatment slots are consistently available to this particularly vulnerable population.

Adult↗
PubMed2000

Consideration of a North American heroin-assisted clinical trial for the treatment of opiate-dependent individuals.

Untreated opiate addiction remains a major public health problem in North America (US and Canada). Increased morbidity and mortality as well as criminal behavior related to untreated opiate dependence constitute significant social and economic burdens. While the principal treatment modality to opiate addiction in North America has been methadone treatment since the 1960s, its reach and effectiveness has been limited; at any given time, only about 25% (US) and 15-20% (Canada) of all opiate addicts are in methadone treatment. Reasons for low levels of treatment participation among this subset of users include perceptions among users that treatment programs are punitive and that the medication is fraught with side effects. In the meantime, alternatives to methadone have been recently approved or are in development, including levo-alpha acetylmethadol and buprenorphine. However, the extent to which they will solve the current problem is still unknown, and therefore development of additional treatment strategies needs to continue. Recent studies of heroin-assisted treatment in Europe (Switzerland, the Netherlands and Great Britain) produced preliminary yet encouraging results in attracting and retaining long-term, treatment-resistant addicts in treatment, as well as improving treatment outcomes. However encouraging, the North American context differs from Europe. A study performed in North America would provide critical information on whether utilizing injectable opiates enhances the overall therapeutic attractiveness and effectiveness of substance abuse treatment to a subset of recalcitrant users. Implications of positive results would expand the continuum of effective interventions in the US and Canada, and increase the number of long-term, treatment-resistant opiate addicts in treatment.

Journal Article↗