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Biomedical subjects

David Vlahov

Publications and source records attributed to David Vlahov.

At least 73 records · Page 4Linked to original sources
PubMed2005

Variants in the Wilms' tumor gene are associated with focal segmental glomerulosclerosis in the African American population.

Wilms' tumor gene (WT1) is important for nephrogenesis and gonadal growth. WT1 mutations cause Denys-Drash and Frasier syndromes, which are characterized by glomerular scarring. To test whether genetic variations in WT1 and WIT1 (gene immediately 5' to WT1) associate with focal segmental glomerulosclerosis (FSGS), patients with biopsy-proven idiopathic and HIV-1-associated FSGS were enrolled in a multicenter study. We genotyped SNP rs6508 located in WIT1 exon 1, three SNPs (rs2301250, rs2301252, rs2301254) in the promoter shared by WT1 and WIT1, rs2234590 in exon 6, rs2234591 in intron 6, rs16754 in exon 7, and rs1799937 in intron 9 of WT1. Cases (n = 218) and controls (n = 281) were compared in the African American population. Stratification by HIV-1 infection status showed that SNPs rs6508, rs2301254, and rs1799937 were significantly associated with FSGS [rs6508 odds ratio (OR) 1.82, P = 0.006; rs2301254 OR 1.65, P = 0.049; rs1799937 OR 1.91, P = 0.005] in the non-HIV-1 group and rs2234591 (OR 0.234, P = 0.011) in the HIV-1 group. Haplotype analyses in the population revealed that seven SNPs were associated with FSGS; five SNPs had the highest contingency score [-log10(P value) = 13.57] in the HIV-1 group. This association could not be explained by population substructure. We conclude that SNPs in WT1 and WIT1 genes are significantly associated with FSGS, suggesting that variants in these genes may mediate pathogenesis by altering WT1 function. Furthermore, HIV-1 infection status interacts with genetic variations in both genes to influence this phenotype. We speculate that nephropathy liability alleles in WT1 pathway genes cause podocyte dysfunction and glomerular scarring.

Black or African American↗
PubMed2005

Prognostic factors for survival differ according to CD4+ cell count among HIV-infected injection drug users: pre-HAART and HAART eras.

To identify prognostic indicators of survival at different CD4 cell levels, independent of highly active antiretroviral therapy (HAART), among injection drug users (IDUs). A community-recruited cohort of injection drug users followed semiannually from 1988 through 2000. Five partially overlapping subcohorts were defined by when participants first reached a CD4 cell level of 351 to 500, 201 to 350, 101 to 200, 51 to 100, or </=50 cells/microL. Prognostic factors were measured at entry into each category. Kaplan-Meier survival estimates for HIV-related death and Cox regression models were constructed by CD4 category. Among the 1030 HIV-infected IDUs, survival improved in the HAART-era with hazard ratios 0.42, 0.36, 0.24, 0.21, and 0.25, respectively, for CD4 cell groups of 500 to 351, 350 to 201, 200 to 101, 100 to 51, and </=50 cells/microL. Shorter survival was associated with prior hospitalization, AIDS, and sexually transmitted disease, with similar effects in the pre-HAART and HAART eras. For the lowest CD4 cell level, prior sepsis or endocarditis, outpatient/emergency room visits, and alcohol use provide additional prognostic value. Survival among HIV-infected IDUs improved since the introduction of HAART, even though utilization of HAART was incomplete. Clinical and behavioral variables provided prognostic information about survival, including substance use indicators.

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

Beyond urban penalty and urban sprawl: back to living conditions as the focus of urban health.

Researchers have long studied urban health, both to describe the consequences of urban living and to design interventions to promote the health of people living in cities. Two approaches to understanding the impact of cities on health have been dominant, namely, urban health penalty and urban sprawl. The urban penalty approach posits that cities concentrate poor people and expose them to unhealthy physical and social environments. Urban sprawl focuses on the adverse health and environmental effects of urban growth into outlying areas. We propose a model that integrates these approaches and emphasizes urban living conditions as the primary determinant of health. The aim of the model is to move beyond describing the health-related characteristics of various urban populations towards identifying opportunities for intervention. Such a shift in framework enables meaningful comparisons that can inform public health activities at the appropriate level and evaluate their effectiveness in improving the health of urban populations. The model is illustrated with two examples from current urban public health practice.

Community Health Services↗
PubMed2005

Ecstasy use and its association with sexual behaviors among drug users in New York City.

In the past two decades, recreational use of ecstasy has become a growing concern in the United States, although most studies assessing ecstasy use have focused on white, middle-class adolescents who use ecstasy during raves and in clubs. We assessed the prevalence of recent ecstasy use among predominantly minority heroin, cocaine, and crack users in New York City and the association between ecstasy and sexual risk above and beyond that of the other drugs. Between 2002 and 2004, injection and non-injection heroin, crack and cocaine users (N= 534) completed a risk behavior questionnaire that included items on ecstasy use. Logistic regression was used to investigate the relation between current ecstasy use and sexual behaviors. Of 534 illicit drug users, 69.7% were aged 25 years or older, 65.2% were Hispanic, 27.9% Black and 77.4% male; 36.7% were injectors. 17.2% of respondents reported recent (last six months) ecstasy use. In a multivariable logistic regression model, current ecstasy use was associated both with initiating sex before age 14 (adjusted odds ratio (AOR) = 1.51) and having two or more partners in the past two months (AOR = 1.86) after adjusting for age at study entry, current cocaine and marijuana use and being an injection drug user. This study suggests that ecstasy use may be more prevalent among urban drug users. Ecstasy use in urban settings, beyond clubs and raves, should continue to be monitored.

Adolescent↗
PubMed2005

Hepatitis B vaccination in correctional health care workers.

BACKGROUND: Data on bloodborne pathogen risk among health care workers (HCWs) employed in the correctional setting are sparse, even though the prevalence of bloodborne infections, including hepatitis B virus (HBV), among inmates is high. To address this, we determined prevalence and correlates of hepatitis B virus vaccination status in correctional health care workers (CHCWs) employed in 3 state correctional health care facilities. METHODS: A confidential, self-administered cross-sectional survey was performed. RESULTS: Four hundred eleven (69.8%) of 588 eligible participants completed the survey. Of these, 264 (64.2%) reported receiving a primary hepatitis B (HB) vaccine series. Vaccination rates varied by state and by job category. Parenteral exposures were not uncommon; 8.6% (n = 24) of clinical CHCWs and 2.0% (n = 7) of nonclinical CHCWs reported one or more needlesticks in the 6-month period prior to the study. Among clinical staff, vaccination correlated with licensure (RN or MD) and race (white) and in nonclinical staff with history of close contact with HBV infected inmates and with needlestick injury. CONCLUSION: Although the HB vaccination rate among CHCWs was generally high, given their potential risk of exposure to HBV, universal vaccination should be encouraged and should include those nonclinicians with job duties that may involve potential exposure to blood/body fluids.

Adult↗
PubMed2005

Impact of drug treatment on subsequent sexual risk behavior in a multisite cohort of drug-using women: a report from the Women's Interagency HIV Study.

BACKGROUND: The evidence that drug treatment programs are associated with changes in sexual behavior and, thus, have prevention benefits beyond addiction is inconclusive. We examined whether entry into drug treatment was associated with subsequent alterations in sexual behavior among a group of drug-using women. METHODS: Data were collected semiannually via structured interviews over 8 years. Generalized estimating equations evaluated the relationship between self-reported drug treatment at each visit and sexual abstinence and consistent condom use in the subsequent 6-month period. RESULTS: In this sample (N = 1,658; mean age, 37.3 years; 57.5% African American; 80.3% HIV positive; 49.6% crack/cocaine users), 40% reported being in a variety of drug treatment programs. Those undergoing drug treatment (vs. those not) were less likely to become sexually active (adjusted odds ratio [AOR], 0.83; 95% confidence interval [CI], 0.76-0.91); this association was unchanged when the frequency of attendance and number of different drug treatment programs were evaluated. Drug treatment was not associated with subsequent consistent condom, regardless of frequency of attendance, but involvement in at least three treatment programs was (AOR, 1.40; 95% CI, 1.00-1.97). CONCLUSIONS: Additional efforts are needed to integrate effective sexual risk reduction programs into drug treatment settings; expanding access to different types of drug treatment modalities may be indicated.

Adult↗
PubMed2005

Cities and population health.

A majority of the world's population will live in urban areas by 2007 and cities are exerting growing influence on the health of both urban and non-urban residents. Although there long has been substantial interest in the associations between city living and health, relatively little work has tried to understand how and why cities affect population health. This reflects both the number and complexity of determinants and of the absence of a unified framework that integrates the multiple factors that influence the health of urban populations. This paper presents a conceptual framework for studying how urban living affects population health. The framework rests on the assumption that urban populations are defined by size, density, diversity, and complexity, and that health in urban populations is a function of living conditions that are in turn shaped by municipal determinants and global and national trends. The framework builds on previous urban health research and incorporates multiple determinants at different levels. It is intended to serve as a model to guide public health research and intervention.

Emigration and Immigration↗
PubMed2005

Interpersonal predictors of depression trajectories in women with HIV.

This article tests an interpersonal model of depression symptom trajectories tailored to the experiences of women with HIV. Specifically, the authors examined how bereavement, maternal role difficulty, HIV-related social isolation, and partner conflict predicted change in depressive symptoms over 5 years in 761 women with HIV, controlling for sociodemographic and clinical health factors. Of these interpersonal characteristics, partner conflict emerged as a robust predictor of change in depressive symptoms in growth curve and cross-lag models. Results highlight the need for interventions focusing on interpersonal issues, particularly intimate relationships, in women with HIV.

Adolescent↗
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

Drug use, misuse, and the urban environment.

Urbanization is probably the single most important demographic shift world-wide throughout the past and the new century and represents a sentinel change from how most of the world's population has lived for the past several thousand years. As urban living becomes the predominant social context for the majority of the world's population, the very ubiquity of urban living promises to shape health directly and to indirectly affect what we typically consider risk factors or determinants of population health. Although a growing body of research is exploring how characteristics of the urban environment may be associated with health (e.g. depression) and risk behaviours (e.g. exercise patterns), relatively little research has systematically assessed how the urban environment may affect drug use and misuse. In this paper we will propose a conceptual framework for considering how different characteristics of the urban environment (e.g. collective efficacy, the built environment) may be associated with drug use and misuse, summarize the existing empiric literature that substantiates elements of this framework, and identify potential directions for future research.

Health Services Accessibility↗
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

Ecstasy use among Hispanic and black substance users in New York City.

Surveillance data suggests that use of ecstasy in the U.S. is predominantly among white adolescent and young adults. To investigate ecstasy use among substance users in New York City we added questions to ongoing efforts to recruit heroin and cocaine users. Of 715 participants recruited, 58.3% were injection drug users (IDUs). The median age was 32 (range 17-64), 76.4% were male, 49.0% were currently homeless, 62.4% were Hispanic, 27.3% were black, and 34.5% were born outside the United States. Overall, 23.4% used ecstasy in their lifetime and 11.9% had used in the last-6 months. In multivariate logistic regression, correlates of lifetime ecstasy use included younger age, being born in the U.S., and current homelessness. We observed a significant interaction between injection drug use and race where, compared to black non-IDUs, Hispanic non-IDUs, and white IDUs were significantly more likely to have a history of lifetime ecstasy use while black IDUs were significantly less likely. These findings are limited to persons who use other drugs, but suggest that further investigation of ecstasy use in minority populations is warranted.

Adolescent↗
PubMed2005

Body habitus in a cohort of HIV-seropositive and HIV-seronegative injection drug users.

We determined anthropometric measurements (including height, weight, circumferences, and skinfolds) and self-reported symptoms related to body habitus changes in 324 HIV-seropositive and HIV-seronegative inner city injection drug users (IDUs) who participated in a substudy from the ALIVE (AIDS Linked to Intravenous Experiences) cohort. Participants who reported lipoatrophy in body parts had consistently lower anthropometric measurements and those reporting adiposity had correspondingly higher anthropometric measurements than participants who did not report these changes. Peripheral lipoatrophy was more common among all HIV-seropositive than HIV-seronegative participants, however, it was not associated with highly active antiretroviral therapy (HAART) (39% HIV-seronegatives; 58% HIV-seropositive not receiving HIV treatment [No Tx]; 49% HAART, p = 0.04). Central adiposity was more common among HAART (52%) than No Tx (26.6%) and HIV-seronegative (42%) participants (p = 0.001). However, waist circumference, while somewhat higher among HAART than No Tx participants, did not differ significantly from HIV-seronegative participants (85.2 cm HIV-seronegatives; 83.3 cm No Tx; 85.8 cm HAART). A large proportion of those who reported peripheral lipoatrophy also reported central lipoatrophy (76.9% HIV-seronegatives; 69.6% No Tx; 66.2% HAART). A large proportion of those who reported central adiposity also reported adiposity of the peripheral sites (88.1% HIV seronegatives; 66.7% No Tx; 74.3% HAART). The combination of lipoatrophy and adiposity was associated with HAART treatment (6% HIV-seronegatives; 3% No Tx; 16% HAART, p = 0.002), but may be driven by the association with adiposity. These data suggest validity of self-reports for body habitus changes among injection drug users.

Adult↗
PubMed2005

A framework for understanding factors that affect access and utilization of treatment for hepatitis C virus infection among HCV-mono-infected and HIV/HCV-co-infected injection drug users.

Treatment for hepatitis C virus (HCV) is rarely received by injection drug users (IDU), particularly those co-infected with HIV. We propose a framework for understanding factors that affect utilization and adherence to HCV therapy among HCV mono-infected and HIV/HCV-co-infected IDU. Provision of treatment requires calculation of risks and benefits including evaluation of a number of time-varying factors that collectively determine a gradient of treatment eligibility, advisability and acceptability, the relative importance of which may differ in co-infected and mono-infected IDU. Treatment eligibility is determined by a number of non-modifiable and modifiable contraindications, the latter of which can change over time rendering patients who were once ineligible eligible. Among those eligible, treatment need can be assessed by liver biopsy and therapy may be deferred in those with no liver disease and started in those with significant liver disease. Among those with moderate disease, further consideration of treatment advisability (medical factors that affect treatment response) and acceptability (individual, provider and environmental barriers) is needed before treatment decisions are made. These factors are dynamic and thus should be continually evaluated even among those who may not initially appear to be ready for treatment. An evaluation of this framework is needed to determine applicability and feasibility. Until then, treatment decisions should be made on an individual basis after careful consideration of these issues by provider and patient and efforts to develop novel strategies for identifying IDU who need treatment most (alternatives to liver biopsy) and multidimensional approaches to deliver treatment for HCV while addressing other factors including HIV infection, depression and drug use should be continued.

Antiviral Agents↗
PubMed2005

Risk of tuberculosis in correctional healthcare workers.

OBJECTIVE: The objective of this study was to determine the prevalence, incidence, and risk factors for occupational infection with tuberculosis among healthcare workers employed in correctional facilities. METHODS: The authors conducted a self-administered survey, clinical interview, and tuberculin skin testing. RESULTS: The overall tuberculin skin test point prevalence rate was 17.7%, the reactivity rate was 2.2%, and the annual incidence was 1.3%. At the multivariate level, after controlling for bacille Calmette-Guérin vaccination, only origin of birth remained significantly associated with prevalence of tuberculosis infection. CONCLUSIONS: Although the prevalence of tuberculin reactivity was high in this population, the risk factors were predominantly demographic rather than occupational. Nevertheless, continued vigilance to control occupational exposure to this and other respiratory pathogens is warranted, given the potential for future outbreaks of tuberculosis, as well as other known and emerging airborne pathogens.

Adult↗