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Biomedical subjects

David Vlahov

Publications and source records attributed to David Vlahov.

At least 163 records · Page 9Linked to original sources
PubMed2003

Racial/ethnic disparities in overdose mortality trends in New York City, 1990-1998.

Racial/ethnic disparities in health and disease have been present in the United States for the past century. Although differences such as individual access to health care and health-related behaviors account for some of these health disparities, it is likely that a combination of individual and contextual-level factors determine the differential rates of disease between racial/ethnic groups. We studied fatal accidental drug overdose in New York City between 1990 and 1998 to describe differences in racial/ethnic patterns over time and to develop hypotheses about factors that might contribute to these differences. During this period, rates of overdose death were consistently higher among blacks and Latinos compared to whites. In addition, cocaine was more common among black decedents, while opiates and alcohol were more common among Latino and white decedents. Differences in situational factors, such as differential likelihood of activating emergency medical response, may in part explain the consistently higher overdose mortality rates observed among minorities. Further study to determine the individual and contextual factors that explain these observed disparities in overdose death may identify effective areas for public health intervention and provide insight into factors underlying racial/ethnic disparities in other health outcomes.

Adolescent↗
PubMed2003

Preliminary evidence of health care provider support for naloxone prescription as overdose fatality prevention strategy in New York City.

Preliminary research suggests that naloxone (Narcan), a short-acting opiate antagonist, could be provided by prescription or distribution to heroin users to reduce the likelihood of fatality from overdose. We conducted a random postal survey of 1100 prescription-authorized health care providers in New York City to determine willingness to prescribe naloxone to patients at risk of an opiate overdose. Among 363 nurse practitioners, physicians, and physician assistants responding, 33.4% would consider prescribing naloxone, and 29.4% were unsure. This preliminary study suggests that a substantial number of New York City health care providers would prescribe naloxone for opiate overdose prevention.

Attitude of Health Personnel↗
PubMed2003

Contextual determinants of drug use risk behavior: a theoretic framework.

Over the past two decades, public health research has emphasized the role of individual risk behaviors, primarily injection and sexual risk behaviors, in the spread of HIV infection. Much less emphasis has been given to understanding the determinants of these risk behaviors. Although individual characteristics are partly responsible for risky injection and sexual behaviors, they do not explain all the interpersonal variability in risk behavior. Contextual factors associated with HIV risk behavior may include structural factors (e.g., availability of services), social norms and attitudes (e.g., social trust), disadvantage (e.g., neighborhood socioeconomic status), and features of the physical environment (e.g., housing quality). This article presents a conceptual framework that incorporates some of the key contextual domains that may affect drug use behavior. It also presents data from a study of street-recruited drug users as an example of the relations between social contextual factors and frequency of injecting drug use, and discusses some methodological challenges in the study of contextual determinants of drug use behavior.

Adult↗
PubMed2003

Factors associated with human herpesvirus type 8 infection in an injecting drug user cohort.

BACKGROUND: Human herpesvirus type 8 (HHV-8) has been infrequently studied in injecting drug user (IDU) populations. GOAL: To estimate the seroprevalence of HHV-8 and risk factors for infection in a cohort of 2,946 IDUs. STUDY DESIGN: In this nested cross-sectional study of 390 IDUs, lytic HHV-8 indirect immunofluorescence assay (IFA) was utilized to estimate the HHV-8 seroprevalence. Multivariate logistic regression was used to assess risk factors for infection. RESULTS: The HHV-8 seroprevalence among the IDUs examined in 1988 was 11.5% (95% confidence interval, 8.5-15.13). HHV-8 seroprevalence in this population was associated with being female (OR = 2.2; = 0.080), having a larger body mass index (OR = 3.0; = 0.053), and history of genital warts (OR = 4.0; = 0.023). Injection of any drug more than daily exhibited an inverse effect on HHV-8 seropositivity (OR = 0.5; = 0.085). CONCLUSION: The seroprevalence of HHV-8 in this population is similar to that seen in the general population, with risk factors being more consistent with sexual behaviors than injection drug use.

Adult↗
PubMed2003

Children of HIV-positive drug-using parents.

OBJECTIVE: Associations between human immunodeficiency virus (HIV) status of injection drug users (IDUs) and their children's psychopathology and social functioning were examined. METHOD: Parents (N = 61) were drawn from an ongoing longitudinal study of inner city, primarily African-American IDUs. Children (N = 79) were 6 to 11 years of age, currently living with the IDU parent. Parental variables included HIV status, apparent and inapparent HIV infection (with HIV-related medical symptoms and/or disclosure of parental HIV status to children; with neither medical symptoms nor disclosure, respectively), presence of HIV-related medical symptoms, HIV disclosure status to each child, and depression as ascertained by the Center for Epidemiologic Studies-Depression. Children's outcomes (competencies, psychiatric symptoms, and disorders) were assessed with the Child Behavior Checklist and the Schedule for Affective Disorders and Schizophrenia for School-Age Children. RESULTS: Children of IDU parents exhibited high rates of psychopathology. Parental HIV infection per se had no discernible impact on children's outcomes. The apparent HIV infection of a parent was associated with an eightfold increase (odds ratio 7.80; 95% confidence interval 1.56-39.09) in the prevalence of disruptive behavior disorders (compared with children of HIV-negative parents). Parental depression was associated with a threefold increase in the prevalence of children's disruptive behavior disorders (odds ratio 3.49, 95% confidence interval 1.11-11.04). CONCLUSIONS: Parental HIV status per se does not seem to have a differential impact on the affected children. The apparent HIV infection of a parent may be associated with children's externalizing symptoms and disorders.

Adult↗
PubMed2003

Awareness and perceptions of a communitywide mental health program in New York city after September 11.

The Project Liberty program was established after the terrorist attacks of September 11, 2001, to offer free mental health services to New York City residents. The authors used data from a random-digit-dial telephone survey to assess public awareness of and willingness to make use of Project Liberty's services. They found that 24 percent of the New York City residents surveyed (480 of 2001 respondents) had heard of Project Liberty four months after September 11. Persons with lower socioeconomic status and those who had psychological symptoms consistent with posttraumatic stress disorder were more likely to say that they would contact Project Liberty. The results of the study suggest that although awareness of this public mental health services was low, Project Liberty was well received among the people who may be most likely to need its services.

Adolescent↗
PubMed2002

A prospective study of adherence and viral load in a large multi-center cohort of HIV-infected women.

OBJECTIVES: To examine the relationship between antiretroviral adherence and viral load, and to determine the predictors of adherence over time in HIV-infected women. DESIGN: Prospective observational study. METHODS: One-hundred sixty-one HIV-infected women who were taking antiretroviral therapy for a median of 3.0 years were recruited from the HIV Epidemiology Research Study, a multicenter cohort study of HIV infection in women. Antiretroviral adherence (percent of doses taken as prescribed) was measured over a 6-month period using MEMS caps. At baseline and follow-up, CD4 lymphocyte count and viral load were measured, and a standardized interview was administered to elicit medication history and drug use behaviors. To examine changes in adherence over time, the mean adherence to all antiretroviral agents was calculated for each monitored month. RESULTS: Adherence varied significantly over time (P < 0.001), ranging from a mean of 64% in month 1 to 45% in month 6. Nearly one-fourth of the participants had a 10% or greater decrease in adherence between consecutive months. Virologic failure occurred in 17% of women with adherence of > or = 88%, 28% of those with 45-87% adherence, 43% of those with 13-44% adherence, and 71% of those with < or = 12% adherence. In multivariate analysis, factors predicting lower adherence included active drug use, alcohol use, more frequent antiretroviral dosing, shorter duration of antiretroviral use, younger age, and lower initial CD4 lymphocyte count. CONCLUSIONS: Antiretroviral adherence is not stable over time. Interventions aimed at monitoring and improving long-term adherence in women are urgently needed.

Adult↗
PubMed2002

Temporal trends in the incidence of human immunodeficiency virus infection and risk behavior among injection drug users in Baltimore, Maryland, 1988-1998.

Although the incidence of and mortality from acquired immunodeficiency syndrome have declined recently in the United States, data are needed on the incidence of human immunodeficiency virus (HIV) and risk behaviors among injection drug users (IDUs). The authors studied the temporal trends of HIV incidence and risk behavior, ascertained through semiannual confidential interviews, between 1988 and 1998 in a cohort of 1,532 HIV-seronegative IDUs in Baltimore, Maryland. An additional 338 HIV-negative drug users were recruited in 1994 and were studied by using the same methods. Overall, 277 persons seroconverted to HIV during 8,826.45 person-years of follow-up, an incidence of 3.14 per 100 person-years. The incidence per 100 person-years declined over time from 4.45 in 1988-1990 to 3.35 in 1991-1994 to 1.84 in 1995-1998, a decline of 12% per year. HIV infections were associated with injection of cocaine, more frequent injection, needle sharing, and injection in a shooting galley. Sexual behavior variables associated with HIV incidence included a sexually transmitted infection, male homosexual behavior, and sex with another IDU. These data suggest that high-risk behavior and HIV incidence among IDUs have decreased recently in Baltimore. Nevertheless, additional prevention strategies are needed in these populations.

Adult↗
PubMed2002

Heat-denatured human immunodeficiency virus type 1 protein 24 antigen: prognostic value in adults with early-stage disease.

CD4(+) lymphocyte count and human immunodeficiency virus (HIV) type 1 RNA level are useful for determining when to initiate antiretroviral therapy but are not used widely in developing countries due to the high cost. Heat-denatured protein 24 (p24) antigen is an inexpensive assay that predicts disease progression among persons with advanced disease but has not been assessed among persons with early-stage disease. Plasma levels of heat-denatured p24 antigen were quantified in baseline study-visit specimens obtained from injection drug users enrolled in a longitudinal cohort study of HIV-1 infection. Of the 494 study participants (median initial CD4(+) lymphocyte count, 518 lymphocytes/mm(3)), 90 (18%) progressed to acquired immunodeficiency syndrome within 5 years. p24 antigen level correlated with both CD4(+) lymphocyte count (r=-0.34; P<.0001) and HIV-1 RNA level (r=0.55; P<.0001). p24 antigen level >5 pg/mL predicted disease progression, comparable with that of cutoff CD4(+) lymphocyte count <350 lymphocytes/mm(3) and HIV-1 RNA level >30,000 copies/mL. Heat-denatured p24 antigen level predicted subsequent clinical disease progression in early-stage HIV-1 infection and correlated with both CD4(+) lymphocyte count and HIV-1 RNA level.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Lack of behavior change after disclosure of hepatitis C virus infection among young injection drug users in Baltimore, Maryland.

We evaluated behavior change after disclosure of a positive hepatitis C virus (HCV) antibody test result among a cohort of young injection drug users (IDUs). Participants underwent semiannual interviews, human immunodeficiency virus (HIV) and HCV antibody testing, and pretest and posttest counseling. We used chi(2) statistics to study changes in the frequencies of high-risk behaviors from baseline to a 6-month follow-up visit among 46 IDUs who had a positive HCV test result and among 60 IDUs who did not have a positive HCV test result or who were unaware of their test result. No significant differences were detected between the 2 groups. Both groups continued to share syringes, needles, and other injection paraphernalia. These findings suggest that young IDUs may not be aware of the risk of HCV infection and highlight the urgent need for post-HCV test guidelines and behavioral interventions to reduce ongoing high-risk behavior that perpetuates the risk of HCV transmission.

Adolescent↗
PubMed2002

Epistatic interaction between KIR3DS1 and HLA-B delays the progression to AIDS.

Natural killer (NK) cells provide defense in the early stages of the innate immune response against viral infections by producing cytokines and causing cytotoxicity. The killer immunoglobulin-like receptors (KIRs) on NK cells regulate the inhibition and activation of NK-cell responses through recognition of human leukocyte antigen (HLA) class I molecules on target cells KIR and HLA loci are both highly polymorphic, and some HLA class I products bind and trigger cell-surface receptors specified by KIR genes. Here we report that the activating KIR allele KIR3DS1, in combination with HLA-B alleles that encode molecules with isoleucine at position 80 (HLA-B Bw4-80Ile), is associated with delayed progression to AIDS in individuals infected with human immunodeficiency virus type 1 (HIV-1). In the absence of KIR3DS1, the HLA-B Bw4-80Ile allele was not associated with any of the AIDS outcomes measured. By contrast, in the absence of HLA-B Bw4-80Ile alleles, KIR3DS1 was significantly associated with more rapid progression to AIDS. These observations are strongly suggestive of a model involving an epistatic interaction between the two loci. The strongest synergistic effect of these loci was on progression to depletion of CD4(+) T cells, which suggests that a protective response of NK cells involving KIR3DS1 and its HLA class I ligands begins soon after HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Modulating influence on HIV/AIDS by interacting RANTES gene variants.

RANTES (regulated on activation normal T cell expressed and secreted), a ligand for the CC chemokine receptor 5, potently inhibits HIV-1 replication in vitro. We tested the influence of four RANTES single nucleotide polymorphism (SNP) variants and their haplotypes on HIV-1 infection and AIDS progression in five AIDS cohorts. Three SNPs in the RANTES gene region on chromosome 17 (403A in the promoter, In1.1C in the first intron, and 3'222C in the 3' untranslated region) are associated with increased frequency of HIV-1 infection. The common In1.1C SNP allele is nested within an intronic regulatory sequence element that exhibits differential allele binding to nuclear proteins and a down-regulation of gene transcription. The In1.1C allele or haplotypes that include In1.1C display a strong dominant association with rapid progression to AIDS among HIV-1-infected individuals in African-American, European-American, and combined cohorts. The principal RANTES SNP genetic influence on AIDS progression derives from the down-regulating RANTES In1.1C allele, although linkage disequilibrium with adjoining RANTES SNPs including a weaker up-regulating RANTES promoter allele (-28G), can modify the observed epidemiological patterns. The In1.1C-bearing genotypes account for 37% of the attributable risk for rapid progression among African Americans and may also be an important influence on AIDS progression in Africa. The diminished transcription of RANTES afforded by the In1.1C regulatory allele is consistent with increased HIV-1 spread in vivo, leading to accelerated progression to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Use of HIV protease inhibitors is associated with left ventricular morphologic changes and diastolic dysfunction.

HIV protease inhibitor (PI) therapy may be associated with cardiac and vascular complications. We assessed the effects of PIs on cardiac function and structure. M-mode, cross-sectional, and Doppler echocardiography were performed in 98 consecutive black adults aged 25 to 45 years with HIV infection who were receiving antiretroviral therapy. Forty-five (56.1%) took PIs (mean duration of PI use: 29.6 +/- 12.2 months). No significant differences between the PI and non-PI groups were found in left ventricular (LV) systolic function and cardiac valve regurgitation. Those who took PIs had a significantly higher interventricular septum thickness (1.1 +/- 0.3 vs. 1.0 +/- 0.2 cm; p =.049), LV posterior wall thickness (1.1 +/- 0.2 vs. 1.0 +/- 0.2; p =.027), and lower ratio of early peak velocity (E wave) to late peak velocity (A wave) (E/A ratio) (1.36 +/- 0.30 vs. 1.53 +/- 0.31; p =.023) than did those who did not take PIs. Linear regression analyses indicated that posterior wall thickness, septum thickness, left atrial dimension, LV mass, and E/A ratios were significantly associated with the log-transformed duration of PI therapy. Despite the proven benefits of PIs in patients with HIV infection, this report demonstrates an association between continued PI intake and LV hypertrophy that should be known and taken into consideration in the analysis of cardiac structure and function in patients with HIV infection.

Adult↗
PubMed2002

Increased use of cigarettes, alcohol, and marijuana among Manhattan, New York, residents after the September 11th terrorist attacks.

The September 11, 2001, terrorist attacks were the largest human-made disaster in the United States since the Civil War. Studies after earlier disasters have reported rates of psychological disorders in the acute postdisaster period. However, data on postdisaster increases in substance use are sparse. A random digit dial telephone survey was conducted to estimate the prevalence of increased cigarette smoking, alcohol consumption, and marijuana use among residents of Manhattan, New York City, 5-8 weeks after the attacks. Among 988 persons included, 28.8% reported an increase in use of any of these three substances, 9.7% reported an increase in smoking, 24.6% reported an increase in alcohol consumption, and 3.2% reported an increase in marijuana use. Persons who increased smoking of cigarettes and marijuana were more likely to experience posttraumatic stress disorder than were those who did not (24.2% vs. 5.6% posttraumatic stress disorder for cigarettes; 36.0% vs. 6.6% for marijuana). Depression was more common among those who increased than for those who did not increase cigarette smoking (22.1 vs. 8.2%), alcohol consumption (15.5 vs. 8.3%), and marijuana smoking (22.3 vs. 9.4%). The results of this study suggest a substantial increase in substance use in the acute postdisaster period after the September 11th attacks. Increase in use of different substances may be associated with the presence of different comorbid psychiatric conditions.

Adolescent↗
PubMed2002

Prospective study of infective endocarditis among injection drug users.

To determine the effect of human immunodeficiency virus (HIV) infection and other factors on infective endocarditis (IE) among injection drug users (IDUs), the incidence of IE was determined according to HIV status in a cohort of IDUs. A nested case-control study assessed IE risk factors. IE incidence (117 cases) was higher among HIV-seropositive than HIV-seronegative IDUs (13.8 vs. 3.3 cases/1000 person-years) during 1988-1998. Multivariate analysis of HIV-infected case patients revealed an inverse association between IE and CD4 lymphocyte count (odds ratio [OR] for 200-499 cells/mm(3), 2.01; OR for <200 cells/mm(3), 3.61) and with alcohol intake (OR for 1-21 drinks/week, 0.43; OR for >21 drinks/week, 0.32). Women had an increased risk of IE (OR, 3.26), as did persons with increasing injection drug use frequency (OR for less than daily use, 3.15; OR for at least daily use, 6.07). This study confirms that IE is more common among IDUs with advanced HIV immunosuppression even after accounting for injection drug use behaviors.

Adult↗
PubMed2002

Protection against persistence of hepatitis C.

BACKGROUND: Neither previous hepatitis C virus (HCV) infection nor vaccination with HCV-derived antigens protects against reinfection. However, HCV infection and vaccination in chimpanzees has been shown to reduce the magnitude and duration of viraemia with re-challenge. We aimed to establish whether similar immunity could be achieved in man. METHODS: From a study of injecting drug users, we identified 164 people who had no evidence of previous HCV infection and 98 individuals who had been previously, but were not currently, infected with HCV. We compared the incidence and persistence of HCV viraemia in these two groups over four consecutive 6-month periods. FINDINGS: Of participants without previous infection, the incidence of HCV infection was 21% (35/164). By contrast, people previously infected were half as likely to develop new viraemia (12% [12/98]), even after accounting for risk behaviour (hazard ratio, 0.45; 95% CI 0.23-0.88). Furthermore, in HIV-1-negative people, those previously infected were 12 times less likely than people infected for the first time to develop persistent infection (odds ratio 0.05, 95% CI 0.01-0.30), and median peak HCV RNA concentration was two logs lower. HCV persisted in six of six HIV-1-positive people, even in one man who had previously cleared HCV infection when he was HIV-1 negative. INTERPRETATION: There is an alarming frequency of HCV infection and persistence among injecting drug users. Our data suggest that immunity against viral persistence can be acquired, and that vaccines should be tested to reduce the burden of HCV-related liver disease.

Adult↗