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Biomedical subjects

David Vlahov

Publications and source records attributed to David Vlahov.

At least 37 records · Page 2Linked to original sources
PubMed2006

Evaluation of an intervention to increase screening colonoscopy in an urban public hospital setting.

Only 50% of New Yorkers aged 50 and over reported ever being screened for colorectal cancer by any modality according to a recent household survey. The objective of this investigation was to assess the impact of a hospital-based intervention aimed at eliminating health care system barriers to timely colorectal cancer screening at Lincoln Medical Center, a large, urban public hospital in one of the nation's poorest census tracts. We conducted a retrospective analysis of all colonoscopies performed over an 11-month period, during which a multi-pronged intervention to increase the number of screening colonoscopies took place. Two "patient navigators" were hired during the study period to provide continuity for colonoscopy patients. A Direct Endoscopic Referral System (DERS) was also implemented. Enhancements to the gastrointestinal (GI) suite were also made to improve operational efficiency. Immediately following the introduction of the patient navigators, there was a dramatic and sustained decline in the broken appointment rates for both screening and diagnostic colonoscopy (from 67% in May of 2003 to 5% in June of 2003). The likelihood of keeping the appointment for colonoscopy after the patient navigator intervention increased by nearly 3-fold (relative risk = 2.6, 95% CI 2.2-3.0). The rate of screening colonoscopies increased from 56.8 per month to 119 per month. The screening colonoscopy coverage provided by this facility among persons aged 50 and over in surrounding Zip codes increased from 5.2 to 15.6% (RR 3.0, 95% CI 1.9-4.7). Efforts to increase the number of screening colonoscopies were highly successful, due in large part to the influence of patient navigators, a streamlined referral system, and GI suite enhancements. These findings suggest that there are significant health-care system barriers to colonoscopy that, when addressed, could have a significant impact on screening colonoscopy rates in the general population.

Adult↗
PubMed2006

The urban environment and sexual risk behavior among men who have sex with men.

Increasingly, studies show that characteristics of the urban environment influence a wide variety of health behaviors and disease outcomes, yet few studies have focused on the sexual risk behaviors of men who have sex with men (MSM). This focus is important as many gay men reside in or move to urban areas, and sexual risk behaviors and associated outcomes have increased among some urban MSM in recent years. As interventions aimed at changing individual-level risk behaviors have shown mainly short-term effects, consideration of broader environmental influences is needed. Previous efforts to assess the influence of environmental characteristics on sexual behaviors and related health outcomes among the general population have generally applied three theories as explanatory models: physical disorder, social disorganization and social norms theories. In these models, the intervening mechanisms specified to link environmental characteristics to individual-level outcomes include stress, collective efficacy, and social influence processes, respectively. Whether these models can be empirically supported in generating inferences about the sexual behavior of urban MSM is underdeveloped. Conceptualizing sexual risk among MSM to include social and physical environmental characteristics provides a basis for generating novel and holistic disease prevention and health promotion interventions.

Homosexuality, Male↗
PubMed2006

Challenges and facilitating factors in sustaining community-based participatory research partnerships: lessons learned from the Detroit, New York City and Seattle Urban Research Centers.

In order to address the social, physical and economic determinants of urban health, researchers, public health practitioners, and community members have turned to more comprehensive and participatory approaches to research and interventions. One such approach, community-based participatory research (CBPR) in public health, has received considerable attention over the past decade, and numerous publications have described theoretical underpinnings, values, principles and practice. Issues related to the long-term sustainability of partnerships and activities have received limited attention. The purpose of this article is to examine the experiences and lessons learned from three Urban Research Centers (URCs) in Detroit, New York City, and Seattle, which were initially established in 1995 with core support from the Centers for Disease Control and Prevention (CDC). The experience of these Centers after core funding ceased in 2003 provides a case study to identify the challenges and facilitating factors for sustaining partnerships. We examine three broad dimensions of CBPR partnerships that we consider important for sustainability: (1) sustaining relationships and commitments among the partners involved; (2) sustaining the knowledge, capacity and values generated from the partnership; and (3) sustaining funding, staff, programs, policy changes and the partnership itself. We discuss the challenges faced by the URCs in sustaining these dimensions and the strategies used to overcome these challenges. Based on these experiences, we offer recommendations for: strategies that partnerships may find useful in sustaining their CBPR efforts; ways in which a Center mechanism can be useful for promoting sustainability; and considerations for funders of CBPR to increase sustainability.

Centers for Disease Control and Prevention, U.S.↗
PubMed2006

Response to overdose among injection drug users.

BACKGROUND: Drug overdose is a leading cause of mortality among illicit drug users. This study characterizes responses to overdose among injection drug users (IDUs) in Baltimore, Maryland, and identifies factors associated with medically inappropriate response. METHODS: A cross-sectional survey was administered to 924 IDUs in an ongoing cohort study between August 2003 and September 2004. Self-reported experiences of witnessing overdose were obtained by structured interview. Multiple logistic regression identified associations between overdose information sources and medically inappropriate responses. RESULTS: Most IDUs (69.7%) reported ever witnessing an overdose. The most common responses were walking the victim around (70.8%), shaking them (64.9%), and inflicting pain (62.6%). One in four (25.8%) injected the victim with salt water. Two thirds (63.4%) called 911, but more than half delayed the call by 5 or more minutes. The most common reason cited for delaying or foregoing the 911 call was the belief that they could revive the victim themselves, followed by fear of police involvement. Most IDUs had received information on how to prevent or respond to an overdose, but most (73.2%) received this information from friends or other drug users. IDUs who got overdose information solely from lay sources were less likely to call 911 (adjusted odds ratio [AOR] = 0.66, 95% confidence interval [CI] = 0.46-0.94) and more likely to inject the victim with salt water (AOR = 2.06, 95% CI = 1.36-3.13) than IDUs who received no information at all. Injection drug users who received information from medical and social services providers only were less likely to delay the 911 call (AOR = 0.35, 95% CI = 0.22-0.72). CONCLUSIONS: Inappropriate overdose responses are widespread among IDUs in Baltimore. Interventions that provide overdose education and reduce police response to overdose events may improve witness response and reduce mortality associated with drug overdose.

Adult↗
PubMed2006

Support for buprenorphine and methadone prescription to heroin-dependent patients among New York City physicians.

Methadone and buprenorphine are treatments for heroin-dependent patients. Methadone is available through highly-regulated treatment centers while buprenorphine was approved in 2002 for prescription by certified physicians. Just prior to the approval of buprenorphine, we conducted a random postal survey of 770 physicians in New York City to determine willingness to prescribe methadone or buprenorphine for heroin-dependent patients to be picked up at a pharmacy. Among 247 respondents, 36.3% would consider prescribing methadone and 17.9% were unsure, while 25.8% would consider prescribing buprenorphine and 31.8% were unsure. Willingness to prescribe methadone or buprenorphine was associated with more recent year of licensure (p = 0.044; p = 0.033), working in a hospital or clinic as opposed to an office setting (p = 0.009; p = 0.024), and being the director of a clinic or program (p = 0.031; p = 0.008). This preliminary study suggests that a substantial proportion of New York City physicians would prescribe methadone or buprenorphine to heroin-dependent patients.

Attitude of Health Personnel↗
PubMed2006

The effects of illicit drug use and HIV infection on sex hormone levels in women.

Drug use and HIV infection may affect sex hormone levels in women. One hundred and ninety-six women with and without a history of illicit drug use (50 HIV-negative and 148 HIV-infected), with regular menses, who never used antiretrovirals, were evaluated. Luteinizing hormone levels were significantly higher in women with a CD4 cell count <200/microl (p < 0.002). Current methadone use was associated with lower levels of total testosterone (p = 0.03) and higher levels of prolactin (p = 0.002); mean estradiol levels were 43% lower in women who used intravenous drugs (p < 0.001). Alcohol and crack cocaine use was not associated with sex hormone levels. Age, race, body mass index and degree of HIV immunosuppression were also associated with differences in sex hormone levels.

Adult↗
PubMed2006

Serum albumin as a prognostic indicator for HIV disease progression.

Low albumin levels have been associated with HIV progression. The objective of this analysis was to confirm this association and to further examine the effect of albumin before and after HIV seroconversion on disease progression. The association was first examined among individuals already infected with HIV at entry into a community-based cohort (n = 453) and further assessed among HIV seroconverters with albumin concentrations measured after (n = 219) and before seroconversion (n = 138). The prognostic effect of albumin on AIDS, AIDS mortality, and all-cause mortality was examined using Cox regression. Among 453 HIV-infected individuals, albumin <35 g/liter was associated with faster progression to AIDS [adjusted relative hazard (ARH), 1.8; 95% confidence interval (CI), 1.2-2.8], AIDS mortality (ARH, 2.2; 95% CI, 1.3-3.8), and all-cause mortality (ARH, 2.4; 95% CI, 1.6-3.5). Analyses restricted to HIV seroconverters were similar. Preseroconversion levels of albumin did not predict outcomes, but HIV seroconversion appeared to lower albumin levels. These data show that albumin <35 g/liter after HIV seroconversion is associated with faster HIV disease progression and suggest that low albumin levels are probably a consequence of HIV infection rather than merely reflective of some individuals inherently having low albumin levels.

Adolescent↗
PubMed2006

Changes in hepatitis C virus (HCV) viral load and interferon-alpha levels in HIV/HCV-coinfected patients treated with highly active antiretroviral therapy.

BACKGROUND: Reports are mixed as to whether highly active antiretroviral therapy (HAART) increases liver transaminase levels or hepatitis C virus (HCV) titers in HIV/HCV-coinfected individuals. It is hypothesized that increases in HCV RNA titers may result from changes in endogenous interferon-alpha (IFN-alpha) production. METHODS: HIV/HCV-coinfected patients receiving HAART were tested at baseline, 1, 2, 3, 6, and 9 months for liver transaminase levels, HIV and HCV viral loads, and IFN-alpha. Linear regression analysis was used to determine the effect of HAART on liver transaminase levels, HCV viral load, and IFN-alpha. RESULTS: Initiating HAART did not increase liver transaminase levels in majority of cases. In patients (n = 30) with baseline HIV titer >10,000 copies/mL, HCV titers increased 0.69 log10 and IFN-alpha decreased -0.96 log10 during HAART, in association with a > or =0.5 log10 decrease in HIV titer. As HIV titers reached their nadir approximately 4 months after initiation of HAART, HCV titers remained 0.54 log10 and IFN-alpha -0.71 log10 above and below baseline levels, respectively. HCV titers and IFN-alpha levels did not change from baseline in patients with baseline HIV titer < or =10,000 copies/mL. CONCLUSIONS: Coinfected patients did not have evidence of hepatoxicity HAART. In patients with baseline HIV titer >10,000 copies/mL, suppression of HIV replication by HAART was associated with an increase in HCV titer and a decrease in endogenous IFN-alpha levels.

Adult↗
PubMed2006

Psychological resilience after disaster: New York City in the aftermath of the September 11th terrorist attack.

Research on adult reactions to potentially traumatic events has focused almost exclusively on posttraumatic stress disorder (PTSD). Although there has been relatively little research on the absence of trauma symptoms, the available evidence suggests that resilience following such events may be more prevalent than previously believed. This study examined the prevalence of resilience, defined as having either no PTSD symptoms or one symptom, among a large (n= 2,752) probability sample of New York area residents during the 6 months following the September 11th terrorist attack. Although many respondents met criteria for PTSD, particularly when exposure was high, resilience was observed in 65.1% of the sample. Resilience was less prevalent among more highly exposed individuals, but the frequency of resilience never fell below one third even among the exposure groups with the most dramatic elevations in PTSD.

Adaptation, Psychological↗
PubMed2006

Consistent effects of TSG101 genetic variability on multiple outcomes of exposure to human immunodeficiency virus type 1.

Tumor susceptibility gene 101 (TSG101) encodes a host cellular protein that is appropriated by human immunodeficiency virus type 1 (HIV-1) in the budding process of viral particles from infected cells. Variation in the coding or noncoding regions of the gene could potentially affect the degree of TSG101-mediated release of viral particles. While the coding regions of the gene were found to lack nonsynonymous variants, two polymorphic sites in the TSG101 5' area were identified that were associated with the rate of AIDS progression among Caucasians. These single-nucleotide polymorphisms (SNPs), located at positions -183 and +181 relative to the translation start, specify three haplotypes termed A, B, and C, which occur at frequencies of 67%, 21%, and 12%, respectively. Haplotype C is associated with relatively rapid AIDS progression, while haplotype B is associated with slower disease progression. Both effects were dominant over the intermediate haplotype A. The haplotypes also demonstrated parallel effects on the rate of CD4 T-cell depletion and viral load increase over time, as well as a possible influence on HIV-1 infection. The data raise the hypothesis that noncoding variation in TSG101 affects the efficiency of TSG101-mediated release of viral particles from infected cells, thereby altering levels of plasma viral load and subsequent disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Heroin and cocaine dependence and the risk of accidental non-fatal drug overdose.

The relation between illicit drug dependence and the likelihood of drug overdose is unclear. We recruited 1,066 habitual drug users for this analysis through street-based outreach in New York City. In this sample, 99.3% of respondents used heroin in the past year and 87.1% of respondents used cocaine; 819 (77.5%) heroin users and 735 (79.2%) cocaine users were severely dependent on either drug respectively. In multivariable models, among heroin users, persons who were severely heroin dependent were less likely (OR = 0.6; 95% CI = 0.4-0.9) to have overdosed on any drug in the past year; among cocaine users, those who were severely cocaine dependent were more likely (OR = 1.6; 95% CI = 1.0-2.6) to have overdosed in the past year. The relation between illicit drug dependence and risk of overdose may vary for different patterns of drug dependence. These observations suggest that overdose prevention interventions, perhaps even those specifically targeting opiate overdose, may be more efficiently directed at individuals exhibiting cocaine dependence.

Adolescent↗
PubMed2006

Primary care and health insurance among women released from New York City jails.

Factors associated with primary care utilization and health insurance coverage were examined among 511 women leaving jail in New York City from 1997-2001. One year after release, roughly half of the sample reported primary care utilization (47%) and health insurance coverage (56%). Neither outcome was more likely among those reporting diabetes, asthma, or depression. Primary care utilization was more likely among those reporting receipt of public benefits, health insurance coverage, moderate social support, avoidance of illegal activity, and HIV seropositivity. Health insurance coverage was associated with receipt of public benefits, hospitalization, primary care, and avoiding re-arrest. This study demonstrated that a majority of women leaving jail, including those with chronic diseases, lack primary care. These data highlight the need to plan for continuity of care from corrections to the community and suggest further that this can be facilitated with provision of health benefits and social support.

Adolescent↗
PubMed2006

Predictors of peritraumatic reactions and PTSD following the September 11th terrorist attacks.

In this study the authors characterize peritraumatic reactions of residents of New York City during and immediately following the September 11th terrorist attacks, identify predictors of those reactions, and identify predictors of PTSD 4 months later. A cross-sectional sample of New York residents (n = 2,001) responded to questions about sociodemographics, historical factors, event-related exposure; acute cognitive, emotional, and physiological reactions to the September 11th terrorist attacks; and current (past month) PTSD symptoms. Factor analyses of peritraumatic reactions yielded three related, but distinct, peritraumatic response patterns - dissociation, emotional reactions, and panic/physiological arousal. Several demographic, historical, and exposure-related variables predicted one or more peritraumatic reaction patterns. After controlling for demographic, historical, and exposure factors, each of the peritraumatic reactions factors, one historical factor and one event-related exposure factor remained as significant predictors of PTSD. These results support a growing literature concerning the predictive value of peritraumatic reactions in relation to PTSD. Implications for preventive efforts and suggestions for future research are discussed.

Acute Disease↗
PubMed2005

Longitudinal predictors of injection cessation and subsequent relapse among a cohort of injection drug users in Baltimore, MD, 1988-2000.

OBJECTIVE: To determine predictors of injection drug use cessation and subsequent relapse among a cohort of injection drug users (IDUs). METHODS: IDUs in Baltimore, MD were recruited through community outreach in 1988-1989. Among IDUs with at least three follow-up visits, parametric survival models for time to injection cessation (>or=6 months) and subsequent relapse were constructed. RESULTS: Of 1327 IDUs, 94.8% were African American, 77.2% were male, median age was 34 years, and 37.7% were HIV-infected. Among 936 (70.5%) subjects who ceased injection, median time from baseline to cessation was 4.0 years. Three-quarters subsequently resumed injection drug use, among whom median time to relapse was 1.0 year. Factors independently associated with a shorter time to cessation were: age <30 years, stable housing, HIV seropositivity, methadone maintenance treatment, detoxification, abstinence from cigarettes and alcohol, injecting less than daily, not injecting heroin and cocaine together, and not having an IDU sex partner. Factors independently associated with shorter time to injection relapse were male gender, homelessness, HIV seropositivity, use of alcohol, cigarettes, non-injection cocaine, sexual abstinence and having a longer time to the first cessation. CONCLUSIONS: This study provides strong support for targeting cessation efforts among young IDUs and severely dependent, unstably housed, and HIV-infected individuals.

Adult↗
PubMed2005

Non-fatal overdose and subsequent drug treatment among injection drug users.

Overdose is a leading cause of death among illicit drug users. Nine hundred twenty-four injection drug users (IDUs) in Baltimore, Maryland, were interviewed to characterize overdose events and determine the circumstances under which they lead to drug treatment. Overall, 366 (39.7%) reported at least one non-fatal drug overdose. Most (96.2%) used heroin on the day of their last overdose and almost half (42.6%) used heroin and alcohol but few (4.1%) used tranquilizers or benzodiazepines. Five percent were in drug treatment when the overdose occurred and 7.1% had been incarcerated 2 weeks prior. One in four IDUs (26.2%) sought drug treatment within 30 days after their last overdose of whom 75% enrolled. Speaking with someone about drug treatment after the overdose was associated with treatment seeking (AOR 5.22; 95% CI: 3.12, 8.71). Family members were the most commonly cited source of treatment information (53.7%) but only those who spoke with spouses, crisis counselors and hospital staff were more likely to seek treatment. Not being ready for treatment (69.6%) and not viewing drug use as a problem (30.7%) were the most common reasons for not seeking treatment and being placed on a waiting list was the most common reason for not subsequently enrolling in treatment (66.7%). Of the IDUs treated by emergency medical technicians, ER staff or hospital staff, only 17.3%, 26.2% and 43.2% reported getting drug treatment information from those sources, respectively. Interventions that provide drug treatment information and enhance motivation for treatment in the medical setting and policies that reduce barriers to treatment entry among motivated drug users are recommended.

Cohort Studies↗
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

AIDS restriction HLA allotypes target distinct intervals of HIV-1 pathogenesis.

An effective acquired immune response to infectious agents mediated by HLA-restricted T-cell recognition can target different stages of disease pathogenesis. We show here that three distinct HLA alleles known to alter the overall rate of AIDS progression act during distinct intervals after HIV-1 infection. The discrete timing of HLA allele influence suggests alternative functional mechanisms in immune defense against this dynamic and chronic immunosuppressive disease.

Acquired Immunodeficiency Syndrome↗