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Biomedical subjects

David Vlahov

Publications and source records attributed to David Vlahov.

At least 109 records · Page 6Linked to original sources
PubMed2004

Increase in sexual risk behavior associated with immunologic response to highly active antiretroviral therapy among HIV-infected injection drug users.

This study identifies factors associated with high-risk sexual and drug injection behaviors among human immunodeficiency virus (HIV)-infected injection drug users (IDUs) after initiation of highly active antiretroviral therapy (HAART). Participants of a large cohort study of IDUs in Baltimore were seen at semiannual visits; blood samples to determine HIV serostatus and CD4+ cell count were obtained, as well as questionnaire data on risk behaviors and medication. Survival analysis conducted for 190 HIV-infected participants who initiated HAART during 1996-2000 revealed that an increase in CD4+ cell count (categorized as an increase of >0 cells/mm3 or of < or =0 cells/mm3) after HAART initiation was independently associated with engaging in any sexual intercourse (adjusted relative hazard [ARH], 1.83; 95% CI, 1.22-2.73) and with a 3-fold increase in the hazard of engaging in unprotected sexual intercourse (ARH, 3.29; 95% CI, 1.57-6.93) after HAART initiation. An increase in CD4+ cell count after HAART initiation was not associated with injection of drugs or needle sharing. Risk reduction counseling remains important, despite improvements in the treatment of HIV infection.

Adult↗
PubMed2004

Syringe distribution to injection drug users for prevention of HIV infection: opinions and practices of health care providers in New York City.

The Expanded Syringe Access Demonstration Program (ESAP), which was intended to increase access to syringes for injection drug users (IDUs), went into effect in New York State on 1 January 2001. ESAP allowed prescription-authorized health care providers to register to distribute syringes without a prescription. In spring 2002, we conducted a random postal survey of 1100 providers in New York City to evaluate involvement in ESAP and willingness to furnish IDUs with syringes. Among 363 nurse practitioners, physicians, and physician assistants responding, 16.9% knew about ESAP, and 2.0% believed they were registered; 50.5% would consider distributing syringes to patients who were IDUs. Most of those unwilling to distribute syringes were concerned about legal and moral issues. More respondents agreed that providers should prescribe syringes than distribute syringes (41.1% vs. 22.7%; P<.0001). These results suggest that many providers are willing to furnish IDUs with syringes but are unaware of the current law.

HIV Infections↗
PubMed2004

High prevalence of occult hepatitis B in Baltimore injection drug users.

Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in a serum or liver in the absence of hepatitis B surface antigen (HBsAg). The prevalence and clinical correlates of occult hepatitis B remain incompletely defined. A cross-sectional study was performed to determine the prevalence of occult hepatitis B in a high-risk cohort composed of 188 injection drug users in Baltimore, Maryland. All individuals had chronic hepatitis C viral infections confirmed by RNA detection and liver biopsy. Serologic assays for HBsAg and core antibody (HBcAb) were performed. Serum HBV DNA was detected using the COBAS HBV AMPLICOR monitor assay (lower limit of detection, 200 HBV copies per milliliter) and a semi-nested polymerase chain reaction (PCR) assay (lower limit of detection, 15 HBV copies per milliliter). Although almost all individuals (96%) were anti-HBC positive, only 8 of 188 (4%) were HBsAg positive. Occult hepatitis B was not identified using the COBAS assay, but was found in 81 of 180 (45%) of individuals using semi-nested PCR. Of the 8 HBsAg positive individuals, HBV DNA was found in 1/8 using the COBAS assay and 6/8 using the nested PCR assay. Overall, liver disease was mild, with a median serum alanine aminotransferase (ALT) of 38 IU/L, median activity grade of 3/18, and median fibrosis stage of 1/6. No association was found between the serum AST (aspartate aminotransferase), activity grade, or stage of liver disease and the presence of occult hepatitis B. Serum ALT levels were slightly higher in patients without occult hepatitis B (46 vs. 35 IU/L), and the median years since first injection drug use was somewhat longer in those without occult hepatitis B (24 vs. 20 years). In conclusion, although further research is needed to assess its clinical significance, there is a high prevalence of occult HBV infection in this cohort of HCV-infected injection drug users.

Adult↗
PubMed2004

Mental health status among ethnic Albanians seeking medical care in an emergency department two years after the war in Kosovo: a pilot project.

STUDY OBJECTIVE: The long-term psychological effects of war are under appreciated in clinical settings. Describing the postwar psychosocial burden on medical care can help direct public health interventions. We performed an emergency department (ED)-based assessment of the mental health status of ethnic Albanian patients 2 years after the North Atlantic Treaty Organization-led bombing of Serbia and Kosovo in 1999. METHODS: This study was conducted July 30, 2001, to August 30, 2001, in the ED of a hospital in Pristina, Kosovo. Investigators collected data through systematic sampling of every sixth nonacute ED patient presenting for care; 87.7% of patients agreed to participate. Respondents completed a structured questionnaire, including demographic characteristics, the Short Form-36, and the Harvard Trauma Questionnaire. RESULTS: All 306 respondents were ethnic Albanians; mean age was 39 years (SD 17.9 years). Of respondents, 58% had become refugees during the war. Two hundred ninety-six (97%) reported experiencing at least one traumatic event during the war; the average number of traumatic events encountered by participants was 6.6. Forty-three (14%) reported symptoms that met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for posttraumatic stress disorder; mean Short Form-36 Mental Component Summary score was 42.1 (SD 12.5). Separate multivariable linear regression models confirmed our belief that older age, female sex, less than a high school education, and having experienced a greater number of traumatic events would be associated with more posttraumatic stress disorder symptoms and lower Mental Component Summary scores. CONCLUSION: Mental health problems among ED patients in Kosovo, particularly among specific vulnerable populations, are a significant public health concern 2 years after the conflict.

Adult↗
PubMed2004

Hispanic ethnicity and post-traumatic stress disorder after a disaster: evidence from a general population survey after September 11, 2001.

PURPOSE: To assess ethnic differences in the risk of post-traumatic stress disorder (PTSD) after a disaster, and to assess the factors that may explain these differences. METHODS: We used data from a representative survey of the New York City metropolitan area (n=2,616) conducted 6 months after September 11, 2001. Linear models were fit to assess differences in the prevalence of PTSD between different groups of Hispanics and non-Hispanics and to evaluate potential explanatory variables. RESULTS: Hispanics of Dominican or Puerto Rican origin (14.3% and 13.2%, respectively) were more likely than other Hispanics (6.1%) and non-Hispanics (5.2%) to report symptoms consistent with probable PTSD after the September 11 terrorist attacks. Dominicans and Puerto Ricans were more likely than persons of other races/ethnicities to have lower incomes, be younger, have lower social support, have had greater exposure to the September 11 attacks, and to have experienced a peri-event panic attack upon hearing of the September 11 attacks; these variables accounted for 60% to 74% of the observed higher prevalence of probable PTSD in these groups. CONCLUSION: Socio-economic position, event exposures, social support, and peri-event emotional reactions may help explain differences in PTSD risk after disaster between Hispanic subgroups and non-Hispanics.

Adult↗
PubMed2004

Prevalence of cryoglobulinemia in hepatitis C virus (HCV) positive patients with and without human immunodeficiency virus (HIV) coinfection.

BACKGROUND: Coinfection with human immunodeficiency virus (HIV) has been shown to influence the natural history of hepatitis C infection. OBJECTIVE: Our interest was to determine if HIV coinfection influences the prevalence of cryoglobulinemia in hepatitis C virus (HCV) infected persons. STUDY DESIGN: A total of 384 HCV RNA positive (234 HIV-infected and 150 HIV-uninfected) participants were tested at two visits, 18 months apart, for HCV and HIV RNA, CD4, and liver enzyme levels. Serum cryoglobulin levels were measured at a subsequent visit for a subset of the sample. RESULTS: HIV-infected participants had significantly higher HCV RNA levels (P < 0.0001) and aspartate transaminase (AST) levels (P < 0.0001), but not alanine transaminase (ALT) levels (P > 0.05) as compared with HIV-uninfected participants. These findings were consistent at both visits and no significant changes were observed between visits. Fifty (19%) of the 264 participants tested had detectable cryoglobulins. No difference was observed in HIV seropositivity among participants with or without cryoglobulinemia (68% versus 61%; odds ratio = 1.34, P = 0.37). However, among HIV coinfected participants, elevated AST levels (P = 0.04) and lower CD4 levels (P = 0.02) were associated with cryoglobulinemia. CONCLUSIONS: While previously reported associations were found between HIV and coinfection with HCV in this study, we did not find an association between HIV infection and cryoglobulinemia.

Adult↗
PubMed2004

Persistence of inconsistent condom use: relation to abuse history and HIV serostatus.

This study longitudinally examines the relation between a history of experiencing childhood and adult physical or sexual abuse, and male condom use by women with or at risk for HIV. Abuse history and prospective condom use data were collected from 214 HIV infected and 189 uninfected women participating in the HIV Epidemiology Research Study (HERS) who were inconsistent condom users at baseline and received two safer sex counseling sessions. Analyses were conducted to assess the association between abuse history and condom use while controlling for sociodemographic variables and other risk factors. HIV-uninfected women with a history of adult physical abuse were five times less likely to report consistent condom use at 1-year follow-up than uninfected women without a history of abuse while holding control variables constant. Expectations of a negative reaction by the partner to suggested condom use did not explain this association. Though in the same direction as in uninfected women, abuse history was not significantly related to consistent condom use among HIV-infected women. These data indicate the need to develop risk prevention strategies tailored to uninfected women with a history of adult abuse. In lieu of specialized interventions, health care providers should assess women's abuse history and supplement HIV prevention counseling with mental health counseling when indicated.

Adolescent↗
PubMed2004

Club drug use among minority substance users in New York City.

Surveillance data suggests that club drug use (Ecstasy, GHB, ketamine, LSD, methamphetamine, PCP and flunitrazepam) has been a predominantly White adolescent and young adult phenomenon in the United States. The authors investigated the use of club drugs among 323 street-recruited minority substance users in northern New York City (66.3% were Hispanic, 23.8% were Black, and 9.9% were White/other race; median age = 32 years old). While Whites were more likely than others to have used club drugs, club drug use among Hispanics and Blacks was not uncommon; 45.3% Hispanics and 56.4% of Blacks reported a lifetime history of club drug use. PCP was the most commonly reported club drug used among all racial/ethnic groups. Further investigation of club drug use in minority populations is warranted.

Adolescent↗
PubMed2004

Consumption of cigarettes, alcohol, and marijuana among New York City residents six months after the September 11 terrorist attacks.

Early analyses following the September 11 terrorist attacks on New York City showed an increase in cigarette, alcohol, and marijuana use, but it was unknown whether these increases would persist. A random-digit dial phone survey was conducted to estimate the prevalence of increased substance use among residents of New York City six to nine months after the attacks. Among 1570 adults, 9.9% reported an increase in smoking, 17.5% an increase in alcohol use, and 2.7% an increase in marijuana use compared to the month before September 11. These increases were comparable to increases reported in the first one to two months after September 11. Persons who increased use of cigarettes were more likely than those who did not to report symptoms consistent with posttraumatic stress disorder (PTSD) in the past month (4.3% and 1.2% respectively). Depression was more common among those who increased use of cigarettes (14.6% and 5.2% respectively), alcohol (11.8% vs. 5.2%), and marijuana (34.1% vs. 5.3%). Among residents living in Manhattan below One Hundred Tenth Street, the prevalence of PTSD and depression declined by more than half in the first six months after September 11, while the increase in substance use did not decline substantially. These results suggest that the increase in substance use after a disaster may be a cause for public health concern in the long-term.

Adolescent↗
PubMed2004

Rapid transmission of hepatitis C virus among young injecting heroin users in Southern China.

BACKGROUND: Hepatitis C virus (HCV) is quickly spread through injection drug use. The prevalence and incidence of HCV in Chinese heroin users has been rarely reported. METHODS: A longitudinal cohort of young injection drug users (IDU) from southern China was established to study the risk factors for blood-borne infections (597 subjects). Individuals underwent analysis for the presence of hepatitis B surface antigen and antibodies to human immunodeficiency virus type 1 (HIV-1), HCV and hepatitis B surface antigen. Using self-reported risk behaviours, multivariate regression analysis was performed for factors associated with HCV prevalence and seroconversion. RESULTS: At baseline, HIV-1 and HCV prevalence was 17% and 72%, respectively. Significant factors associated with HCV seroprevalence included age >25 years (odds ratio [OR] = 1.71) and injection drug use for >2 years (OR = 2.60). HCV prevalence within one year of starting heroin use was 57% for any route of administration, and 80% if restricted to injectors. After two 6-month follow-up visits, 56 out of 159 baseline HCV seronegative individuals (148.9 total person years [py]), underwent seroconversion at an incidence rate of 37.6 per 100 py. Individuals who reported injection drug use were more likely to undergo HCV seroconversion (rate ratio [RR] = 6.59). CONCLUSIONS: HCV infection is rapidly acquired in heroin users who adopt injection in southern China. This study emphasizes the urgent need to implement and expand injection prevention and primary substance abuse prevention programmes in China.

Adult↗
PubMed2004

Updating the infection risk reduction hierarchy: preventing transition into injection.

Current approaches to prevention of blood-borne infections in injection drug users include referral to drug abuse treatment, access to sterile syringes, bleach disinfection of injection equipment, and education about not sharing equipment. However, rates of some blood-borne infections (e.g., hepatitis C virus) remain elevated among injection drug users, especially early after initiation into injection drug use. With lower infection rates in noninjectors and transition into injection drug use occurring most commonly among these noninjectors, prevention of transition into injection drug use as an additional step to reduce risk for acquisition and transmission of blood-borne infections merits closer attention.

Blood-Borne Pathogens↗
PubMed2004

Hepatitis C incidence--a comparison between injection and noninjection drug users in New York City.

Hepatitis C virus (HCV) burdens injection drug users (IDUs) with prevalence estimated from 60-100% compared to around 5% among noninjection drug users (non-IDUs). We present preliminary data comparing the risk for HCV among IDUs and non-IDUs to inform new avenues of HCV prevention and intervention planning. Two cohorts, new IDUs (injecting < or =3 years) and non-IDUs (smoke/sniff heroine, crack or cocaine < or =10 years), ages 15-40, were street-recruited in New York City. Participants underwent risk surveys and HCV serology at baseline and 6-month follow-up visits. Person-time analysis was used to estimate annual HCV incidence. Of 683 non-IDUs, 653 were HCV seronegative, 422 returned for at least 1 follow-up visit, and 1 became HCV seropositive. Non-IDUs contributed 246.3 person-years (PY) yielding an annual incident rate of 0.4/100 PY (95% Confidence Interval [CI]=0.0-1.2). Of 260 IDUs, 114 were HCV seronegative, 62 returned for at least 1 follow-up visit, and 13 became HCV seropositive. IDUs contributed 36.3 PY yielding an annual incidence rate of 35.9/100 PY (95%CI=19.1-61.2). Among IDUs, HCV seroconverters tended to be younger (median age 25 vs. 28, respectively), and inject more frequently (61.5% vs. 34.7%, respectively) than non-seroconverters. These interim data suggest that IDUs may have engaged in high-risk practices prior to being identified for prevention services. Preventing or at least delaying transition into injection could increase opportunity to intervene. Identifying risk factors for transition into injection could inform early prevention to reduce onset of injection and risk of HCV.

Adolescent↗
PubMed2004

Comparison of HIV infection risk behaviors among injection drug users from East and West Coast US cities.

This study assessed whether behavioral differences explained higher human immunodeficiency virus (HIV) seroprevalence among injection drug users (IDUs) in three East Coast versus two West Coast cities in the United States. Sociodemographic, sexual, and injecting information were collected during semiannual face-to-face interviews. Baseline data from New York City; Baltimore, Maryland; and New Haven, Connecticut, were compared with data from Los Angeles, California, and San Jose, California. Among 1,528 East Coast and 1,149 West Coast participants, HIV sero-prevalence was 21.5% and 2.3%, respectively (odds ratio [OR] 11.9; 95% confidence interval [CI] 7.9-17.8). HIV risk behaviors were common among IDUs on both coasts, and several were more common among West Coast participants. Adjusting for potential risk factors, East (vs. West) Coast of residence remained highly associated with HIV status (adjusted OR 12.14; 95% CI 7.36-20.00). Differences in HIV sero-prevalence between East and West Coast cities did not reflect self-reported injection or sexual risk behavior differences. This suggests that other factors must be considered, such as the probability of having HIV-infected injection or sexual partners. Prevention efforts are needed on the West Coast to decrease HIV-associated risk behaviors among IDUs, and further efforts are also needed to reduce HIV incidence on the East Coast.

Adolescent↗
PubMed2004

The New York Cancer Project: rationale, organization, design, and baseline characteristics.

Cancer is the second leading cause of death in New York City, with nearly 15,000 deaths each year. The urban setting of New York City provides ready access to large and diverse populations for whom racial/ethnic disparities in cancer risk and outcomes can be examined. A new cohort study was undertaken with several aims: (1) to provide a database and biorepository for studies of cancer etiology and pathogenesis, including host genetics; (2) to differentiate risk factors that contribute to racial/ethnic disparities in cancer risk, prevention, control, incidence, mortality, and survival; (3) to provide timely data on cancer risk and preventive behaviors that can be used to mobilize and then evaluate public health programs. Scientists from multiple institutions contributed to protocol design and implementation. Study instruments included demographics, personal and family history of cancer, risk and prevention efforts. End points include linkage with registries and medical record reviews. Using venue-based sampling with quotas, 18,187 adults aged 30 years or older were recruited over a year to undergo a baseline questionnaire, venipuncture, and contact information. The sample was 39% male, 37% older than 50 years, 58% white, 20% African American, 18% Hispanic, and 9% Asian. In terms of family history of cancer, 21% reported mother, 21% reported father, and 5.9% reported both parents with cancer; 8.5% reported any sibling with cancer. At baseline, 1,231 participants reported prior cancer. Showing the feasibility of constructing a cohort based in New York City, plans proceed for additional recruitment and analyses on the salient questions about cancer.

Epidemiologic Research Design↗
PubMed2004

Cities and health: history, approaches, and key questions.

The majority of the world's population will live in cities in the next few years, and the pace of urbanization worldwide will continue to accelerate over the coming decades. Such a dramatic demographic shift can be expected to have an impact on population health. Although there has been historic interest in how city living is associated with health, this interest has waxed and waned and a cogent framework has yet to evolve that encompasses key issues in urban health. In this article, the authors discuss three alternate approaches to the study of urban health today; these include considering urban health from the perspective of a presumed urban health penalty, from an urban sprawl perspective, and more comprehensively, considering how urban living conditions may be associated with health. The authors also propose three key questions that may help guide the study and practice of urban health in coming decades. These include considering what specific features of cities are causally related to health, the extent to which these features are unique to a particular city or are different between cities, and ultimately, to what extent these features of cities are modifiable in order to allow interventions that can improve the health of urban populations.

Cities↗