Biomedical subjects

David Vlahov

Publications and source records attributed to David Vlahov.

At least 91 records · Page 5Linked to original sources

PubMed2005

The relationship between non-injection drug use behaviors on progression to AIDS and death in a cohort of HIV seropositive women in the era of highly active antiretroviral therapy use.

AIMS: To evaluate the effects of longitudinal patterns and types of non-injection drug use (NIDU) on HIV progression in the highly active antiretroviral therapy (HAART) era. DESIGN: Women's Interagency HIV Study (WIHS), a prospective cohort study conducted at six US sites. METHODS: Data were collected semi-annually from 1994 to 2002 on 1046 HIV(+) women. Multivariate Cox proportional hazards modeling was used to estimate relative hazards for developing AIDS and for death by pattern and type of NIDU. FINDINGS: During follow-up, 285 AIDS events and 287 deaths, of which 177 were AIDS-related, were reported. At baseline, consistent and former NIDU was associated with CD4(+) counts of < 200 cells/microl (43% and 46%, respectively) and viral load > 40,000 copies/ml (53% and 55%, respectively). Consistent NIDU reported less HAART use (53%) compared with other NIDU patterns. Stimulant use was associated with CD4(+) cell counts of < 200 cells/microl (53%) and lower HAART initiation (63%) compared with other NIDU types. In multivariate analyses, progression to AIDS was significantly higher among consistent (RH = 2.52), inconsistent (RH = 1.63) and former (RH = 1.56) users compared with never users; and for stimulant (RH = 2.04) and polydrug (RH = 1.65) users compared with non-users. Progression to all-cause death was higher only among former users (RH = 1.48) compared with never users in multivariate analysis. NIDU behaviors were not associated with progression to AIDS-related death. CONCLUSIONS: In this study, pattern and type of NIDU were associated with HIV progression to AIDS and all-cause mortality. These differences were associated with lower HAART utilization among consistent NIDU and use of stimulants, and poor baseline immunological and virological status among former users.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Urban built environment and depression: a multilevel analysis.

STUDY OBJECTIVE: To assess the relations between characteristics of the neighbourhood internal and external built environment and past six month and lifetime depression. DESIGN AND SETTING: Depression and sociodemographic information were assessed in a cross sectional survey of residents of New York City (NYC). All respondents were geocoded to neighbourhood of residence. Data on the quality of the built environment in 59 NYC neighbourhoods were collected from the United Status census, the New York City housing and vacancy survey, and the fiscal 2002 New York City mayor's management report. MAIN RESULTS: Among 1355 respondents, residence in neighbourhoods characterised by a poor quality built environment was associated with greater individual likelihood of past six month and lifetime depression in multilevel models adjusting for individual age, race/ethnicity, sex, and income and for neighbourhood level income. In adjusted models, persons living in neighbourhoods characterised by poorer features of the built environment were 29%-58% more likely to report past six month depression and 36%-64% more likely to report lifetime depression than respondents living in neighbourhoods characterised by better features of the built environment. CONCLUSIONS: Living in neighbourhoods characterised by a poor quality built environment is associated with a greater likelihood of depression. Future prospective work designed to assess potential mechanisms underlying these associations may guide public health and urban planning efforts aimed at improving population mental health.

Adolescent↗

PubMed2005

Urban health: evidence, challenges, and directions.

Urbanization is one of the most important demographic shifts worldwide during the past century and represents a substantial change from how most of the world's population has lived for the past several thousand years. The study of urban health considers how characteristics of the urban environment may affect population health. This paper reviews the empirical research assessing urban living's impact on population health and our rationale for considering the study of urban health as a distinct field of inquiry. The key factors affecting health in cities can be considered within three broad themes: the physical environment, the social environment, and access to health and social services. The methodologic and conceptual challenges facing the study of urban health, arising both from the limitations of the research to date and from the complexities inherent in assessing the relations among complex urban systems, disease causation, and health are discussed.

Causality↗

PubMed2005

Probable cigarette dependence, PTSD, and depression after an urban disaster: results from a population survey of New York City residents 4 months after September 11, 2001.

Disaster exposure may exacerbate psychopathology and substance-related disorders. Four months after September 11, 2001, using random-digit dialing to contact a representative sample of adults (N = 2001) living in New York City, we assessed cigarette smoking and symptoms of probable cigarette dependence using measures from the National Survey on Drug Use and Health. A total of 36.8% of smokers reported increased cigarette use; 10.4% of respondents reported three or more symptoms of cigarette dependence and were considered cases of probable cigarette dependence based on DSM-IV criteria. Cases were more likely to report an increase in cigarette use since September 11 than non-cases (69.4% among cases vs. 2.2% among non-cases, p < 0.001). Cases were more likely to have probable posttraumatic stress disorder (PTSD) and depression than non-cases (18.1% vs. 5.7% for PTSD, p < 0.001; 23.6% vs. 6.0% for depression, p < 0.001). Increased cigarette use since September 11 was associated with probable PTSD among cases (23.4% vs. 6.4%, p = 0.011) and non-cases (15.1% vs. 5.5%, p = 0.034) but was associated with probable depression only among cases of probable cigarette dependence (28.3% vs. 13.3%, p = 0.027). This study showed the co-occurrence of probable cigarette dependence with increased cigarette use and the co-occurrence of probable cigarette dependence with probable PTSD and depression after September 11.

Adolescent↗

PubMed2005

Income inequality and risk of suicide in New York City neighborhoods: a multilevel case-control study.

Evidence on the relationship between income inequality and suicide is inconsistent. Data from the New York City Office of the Chief Medical Examiner for all fatal injuries was collected to conduct a multilevel case-control study. In multilevel models, suicide decedents (n=374) were more likely than accident controls (n=453) to reside in neighborhoods with greater income inequality even after controlling for individual characteristics; this relation was modified by age with an effect overall and among decedents aged 15-34 but not among decedents 35-64. These data suggest that income inequality may contribute to the risk of suicide in younger adults.

Adolescent↗

PubMed2005

Childhood sexual abuse and age at initiation of injection drug use.

OBJECTIVES: We examined the relation between childhood sexual abuse and injection drug use initiation among young adult injection drug users. METHODS: We used mixed effect linear models to compare age at first injection among 2143 young injection drug users by first sexual abuse age categories. RESULTS: The participants were predominantly male (63.3%) and White (52.8%). Mean age and age at first injection were 23.7 and 19.6 years, respectively; 307 participants (14.3%) reported childhood sexual abuse. After adjustment for gender, race/ethnicity, noninjection drug use before first injection drug use, and recruitment site, childhood sexual abuse was independently associated with younger age at first injection. CONCLUSIONS: Childhood sexual abuse was associated with earlier initiation of injection drug use. These data emphasize the need to integrate substance abuse prevention with postvictimization services for children and adolescents.

Adolescent↗

PubMed2005

Effects of race, neighborhood, and social network on age at initiation of injection drug use.

OBJECTIVES: We investigated individual- and neighborhood-level factors associated with adolescent initiation of injection drug use. METHODS: Injection drug users (IDUs) who had been injecting 2 to 5 years underwent HIV testing and completed a sociobehavioral risk survey. Modeling techniques accounting for intraneighborhood correlations were used in data analyses. RESULTS: Adolescent-initiating IDUs were less likely than adult-initiating IDUs to report high-risk sex and injection behaviors and more likely to report high-risk networks. African American IDUs from neighborhoods with large percentages of minority residents and low adult educational levels were more likely to initiate injection during adolescence than White IDUs from neighborhoods with low percentages of minority residents and high adult education levels. CONCLUSIONS: Racial segregation and neighborhood-level educational attainment must be considered when drawing inferences about age at initiation of injection drug use and related high-risk behaviors.

Adolescent↗

PubMed2005

Racial/ethnic differences in screening for colon cancer: report from the New York Cancer Project.

OBJECTIVE: To determine whether racial/ethnic differences in colon cancer screening are independent of socioeconomic and personal risk factors. DESIGN: Baseline cross-section for a prospective cohort. METHOD: We recruited adults between 2000 and 2002 to undergo a questionnaire and venipuncture to study cancer risks. RESULTS: Among 5595 adults over 50 years old, 40.3% reported sigmoidoscopy or colonoscopy within the prior five years; rates were 48.0% for Whites, 32.8% for Blacks, 27.9% for Hispanics, 30.3% for Asians, and 33.3% for others. Adjusting for age, gender, access to care (as income and insurance), and risk profile (as cancer in family, smoking, and obesity), Blacks and Hispanics were less likely to have been screened than Whites. CONCLUSIONS: Screening for colon cancer is low, especially among racial/ethnic minorities. Sociocultural factors merit closer attention.

Adult↗

PubMed2005

Suicidal ideation among African-American non-injection drug users.

The objective of the study was to explore correlates of suicidal ideation among African Americans in a community-based cohort in Baltimore, Md. Participants had initiated use of heroin, crack, or cocaine by means other than injection in the prior 10 years. An interview-administered questionnaire collected information regarding drug use history, depressive symptoms, drug dependence, and suicidal thoughts and attempts within the past six months. Multiple logistic regression was used to identify factors independently associated with suicidal ideation. Of 148 persons, median age was 27 years, and 60.8% were female. Suicidal ideation was reported by 21.6% of participants. Those reporting suicidal ideation were significantly more likely to be dependent on two or more drugs (adjusted odds ratio=2.93, 95% confidence interval = 1.25, 6.88). Our findings underscore the need to integrate treatment for psychiatric comorbidity and drug dependence and target these services toward young, African-American drug users.

Adolescent↗

PubMed2005

Drug and alcohol use as determinants of New York City homicide trends from 1990 to 1998.

In this population-level study, we analyzed how well changes in drug and alcohol use among homicide victims explained declining homicide rates in New York City between 1990 and 1998. Victim demographics, cause of death, and toxicology were obtained for all homicide (N = 12573) and accidental death victims (N = 6351) between 1990 and 1998 from the Office of the Chief Medical Examiner of New York (OCME). The proportion of homicide and accident decedents positive for cocaine fell between 1990 and 1998 (13% and 9% respectively); the proportion of homicide and accident decedents positive for opiates and/or alcohol did not change significantly. Changing patterns of drug and alcohol use by homicide victims were comparable to changing patterns of drug and alcohol use in accident victims, suggesting that changes in drug and alcohol use among homicide victims between 1990 and 1998 cannot solely explain the decline in NYC homicide rates.

Adolescent↗

PubMed2004

Dominant effects of CCR2-CCR5 haplotypes in HIV-1 disease progression.

Three haplotypes for the CCR2-CCR5 region previously have been shown to affect AIDS progression; however, it is not known if the protective and accelerating effects of the haplotypes are relatively constant throughout infection or exert their effects early or late in HIV type 1 infection. The authors report the relative contributions to AIDS progression of CCR2 64I, CCR5 Delta32, and the CCR5 promoter haplotype +.P1.+ in the GRIV cohort, which included patients representing the extremes of the distribution for AIDS progression: rapid progressors (RP) who developed CD4 T-cell counts of <300/ mm within 3 years after the last HIV-1-seronegative test and slow progressors (SP) who were HIV-1 infected for > or =8 years with CD4 T-cell counts of >500/mm. Comparing the RP with a seroconverter control group including intermediate progressors to AIDS, we observed the early protective effect of CCR5 Delta32 (odds ratio = 0.25; P = 0.007) was similar in strength to the early susceptible effect of CCR5 +.P1.+ (odds ratio = 2.1, P = 0.01). Comparison of the intermediate control group to the SP showed weaker and less significant odd ratios, suggesting that the effect of these factors tended to be stronger on early progression; the tendency towards a disproportionately early effect was significant for CCR5 Delta32 (P = 0.04) but not for CCR5 +.P1.+ (P = 0.12). Follow-up of SP demonstrated that these polymorphisms have little effect after 8 years, because the subset of SP who had progression after study entry had the same genotype distribution as the global population of SP, suggesting that factors other than CCR5 or CCR2 genetic variants must be responsible for the long-term maintenance of nonprogression.

Acquired Immunodeficiency Syndrome↗

PubMed2004

The effect of hepatitis C on progression to AIDS before and after highly active antiretroviral therapy.

OBJECTIVES: To assess the effect of infection with hepatitis C virus (HCV) on the progression of human immunodeficiency virus (HIV) disease, before and after the introduction of highly active antiretroviral therapy (HAART). METHODS: We used data from a multi-centre prospective study of HIV seroconverters. Survival analyses were performed to compare the progression to AIDS by HCV serostatus in the period before HAART (i.e. June 1991-May 1996) and in the HAART era (i.e. June 1996-June 2001), controlling for duration of HIV infection. RESULTS: Among the 1052 persons enrolled, 595 (56.6%) were co-infected; the median follow-up time was 9.7 years. Adjusting for demographic variables (age at HIV seroconversion and gender), HCV infection had no effect on the progression to AIDS in the pre-HAART era [relative hazard (RH) = 0.84; 95% confidence interval (CI), 0.63-1.11], whereas it increased the risk in the HAART era (RH = 1.77; 95% CI, 1.15-2.73). In the HAART era, the proportion of person-time spent on HAART out of the total time at risk was significantly lower among co-infected persons (30 versus 40% for non-co-infected persons; P-value = 0.001); no significant difference was found for dual-therapy (29 versus 25%, respectively; P-value = 0.205); a significant difference was found for mono-therapy (15 versus 8%, respectively; P-value < 0.001). CONCLUSIONS: HCV infection was not a determinant of HIV disease progression in the pre-HAART era, whereas since the introduction of HAART, co-infected individuals seem to have had a faster disease progression. This may in part be explained by differences in person-time spent on different antiretroviral regimens.

AIDS-Related Opportunistic Infections↗

PubMed2004

Mortality in HIV-seropositive versus -seronegative persons in the era of highly active antiretroviral therapy: implications for when to initiate therapy.

BACKGROUND: The optimal time to initiate highly active antiretroviral therapy (HAART) remains unclear. METHODS: Five hundred eighty-three human immunodeficiency virus (HIV)-seropositive and 920 HIV-seronegative injection drug users (IDUs) were followed from 1997 to 2000. HIV-seropositive participants were categorized according to receipt of HAART (either initiated or switched to HAART) and initial CD4 cell count. Survival analysis that included delayed-entry and Cox proportional-hazards models was used to evaluate the effect of HAART, with adjustments for factors associated with access to HAART. RESULTS: Compared with HIV-seronegative participants, overall survival was similar in HIV-seropositive participants who received HAART at >350 CD4 cells/microL, but mortality was higher both in participants with >350 CD4 cells/microL who did not receive HAART and in participants who received HAART at 200-350 CD4 cells/microL (mortality rates, 19.9, 24.0, 43.0, and 50.5/1000 person-years, respectively). In proportional-hazards models in which HIV-seronegative participants were the reference group and in which age, sex, race, frequency of drug use, substance-abuse treatment, and health-care utilization were adjusted for, hazard ratios were 1.01 (95% confidence interval [CI], 0.41-2.45), 2.28 (95% CI, 1.38-3.78), and 2.09 (95% CI, 1.07-4.10) for the latter 3 groups. In HIV-seropositive participants, HAART significantly improved survival when initiated at CD4 cell counts < 200 cells/microL. CONCLUSIONS: Survival of HIV-seropositive participants receiving HAART approximated that of HIV-seronegative participants only when therapy was given at CD4 cell counts > 350 cells/microL. These data, restricted to IDUs, suggest initiating or switching to HAART at higher CD4 cell levels than are currently recommended.

Adult↗

PubMed2004

Association between injection practices and duration of injection among recently initiated injection drug users.

BACKGROUND: Earlier studies suggest higher infection risk among recently initiated injection drug users (IDUs) than more experienced users. Whether IDUs' risky injection practices rise progressively with duration of injection or frequency of practices is higher near initiation and then taper remains an open question. METHODS: Recently initiated IDUs were street recruited and interviewed between 1997 and 1999 as part of a multisite cohort study in five US urban cities. Recent risky injection practices (injecting with others and injecting on average more now) were examined across three cross-sections defined by duration of injection: 0-1 year, 2-3 years, and 4-6 years. RESULTS: The IDU groups of <2 years duration (n = 691) and 2-3 years duration (n = 697) had higher odds than the 4-6 year group (n = 520) of reporting injecting with others (Odds Ratio, OR = 1.52, and OR = 1.47, respectively) and injecting on average more now (OR = 1.44 and OR = 1.44, respectively). The associations remained after multivariate adjustment for demographic variables. CONCLUSIONS: These data on recently initiated IDUs suggest that risky injection practices were more frequent earlier than later within the first 6 years of initiation, emphasizing that outreach prevention needs to identify and intervene with IDUs early.

Adolescent↗

PubMed2004

HLA and NK cell inhibitory receptor genes in resolving hepatitis C virus infection.

Natural killer (NK) cells provide a central defense against viral infection by using inhibitory and activation receptors for major histocompatibility complex class I molecules as a means of controlling their activity. We show that genes encoding the inhibitory NK cell receptor KIR2DL3 and its human leukocyte antigen C group 1 (HLA-C1) ligand directly influence resolution of hepatitis C virus (HCV) infection. This effect was observed in Caucasians and African Americans with expected low infectious doses of HCV but not in those with high-dose exposure, in whom the innate immune response is likely overwhelmed. The data strongly suggest that inhibitory NK cell interactions are important in determining antiviral immunity and that diminished inhibitory responses confer protection against HCV.

Adolescent↗

PubMed2004

War-related psychological sequelae among emergency department patients in the former Republic of Yugoslavia.

BACKGROUND: Residents of the Republic of Serbia faced civil war and a NATO-led bombing campaign in 1999. We sought to assess the burden of metal health dysfunction among emergency department (ED) patients presenting for care three years post-war in Serbia. METHODS: This study was conducted during July and August 2002 at two sites: a university hospital ED in Belgrade, Serbia and an ED in a remote district hospital serving a Serbian enclave in Laplje Selo, Kosovo. Investigators collected data on a systematic sample of non-acute patients presenting to the ED. All respondents completed a structured questionnaire assessing demographics and symptoms of post-traumatic stress disorder (PTSD) (using the Harvard Trauma Questionnaire), and major depression (using the Center for Epidemiologic Studies Depression Scale). RESULTS: A total of 562 respondents participated (310 in Belgrade, 252 in Laplje Selo); the response rate was 83.8%, 43% were female, and mean age was 37.6 years (SD = 13.4). Overall, 73 (13.0%) participants had symptoms consistent with PTSD, and 272 (49.2%) had symptoms consistent with depression. Sixty-six respondents had both disorders (11.9%). In separate multivariable logistic regression models, predictors of PTSD were refugee status and residence in Laplje Selo, and predictors of depression were older age, current unemployment, and lower social support. CONCLUSIONS: Three years post-war, symptoms of PTSD and major depression in Serbia remained a significant public health concern, particularly among refugees, those suffering subsequent economic instability, and persons living in rural, remote areas.

Adult↗

PubMed2004

High-risk behavior and potential transmission of drug-resistant HIV among injection drug users.

Evidence of increasing prevalence of drug resistance among recent HIV seroconverters indicates a growing public health concern and warrants an examination of the problem from a prevention perspective. Among 638 HIV-infected injection drug users (IDUs) completing 2731 visits between December 1996 and February 2000 in an ongoing cohort study in Baltimore, Maryland, factors associated with unprotected sex and needle sharing were determined. Participants were classified as being at higher or lower risk of HIV and of drug-resistant HIV transmission based on viral load, antiretroviral therapy use, and reported high-risk behavior. Stored plasma of those at higher risk of drug-resistant HIV transmission was tested for resistance by VirtualPhenotype (Vircolab, Rockville, MD). Women were nearly twice as likely as men to engage in unprotected sex, and IDUs were more likely to have unprotected sex if their sexual partners were also HIV infected. IDUs were at higher risk of HIV and drug-resistant HIV transmission at 19% and 6% of all visits, respectively. Participants were infected with drug-resistant HIV at 14% of visits when they were at higher risk of HIV transmission. Intensive risk reduction counseling is needed and must be integrated into routine HIV clinical care.

Adolescent↗

PubMed2004

A high-density admixture map for disease gene discovery in african americans.

Admixture mapping (also known as "mapping by admixture linkage disequilibrium," or MALD) provides a way of localizing genes that cause disease, in admixed ethnic groups such as African Americans, with approximately 100 times fewer markers than are required for whole-genome haplotype scans. However, it has not been possible to perform powerful scans with admixture mapping because the method requires a dense map of validated markers known to have large frequency differences between Europeans and Africans. To create such a map, we screened through databases containing approximately 450000 single-nucleotide polymorphisms (SNPs) for which frequencies had been estimated in African and European population samples. We experimentally confirmed the frequencies of the most promising SNPs in a multiethnic panel of unrelated samples and identified 3011 as a MALD map (1.2 cM average spacing). We estimate that this map is approximately 70% informative in differentiating African versus European origins of chromosomal segments. This map provides a practical and powerful tool, which is freely available without restriction, for screening for disease genes in African American patient cohorts. The map is especially appropriate for those diseases that differ in incidence between the parental African and European populations.

Black or African American↗