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Biomedical subjects

A R Moss

Publications and source records attributed to A R Moss.

At least 19 recordsLinked to original sources
PubMed2001

Hepatitis C virus infection and needle exchange use among young injection drug users in San Francisco.

Young injection drug users (IDUs) in San Francisco may be at high risk for hepatitis C virus (HCV) infection despite access to several needle exchange venues. The authors conducted a cross-sectional study from 1997 to 1999 in San Francisco to estimate the prevalence and incidence of antibody to HCV (anti-HCV) among street-recruited IDUs under age 30, and to examine risk behaviors and sources of sterile needles. Among 308 participants, the prevalence of anti-HCV was 45%. Using statistical modeling, incidence of HCV infection was estimated to be 11 per 100 person years. Independent risk factors for anti-HCV included age (odds ratio [OR], 1.17 per year; 95% confidence interval [CI], 1.05-1.30), years injecting (OR, 1.21 per year; 95% CI, 1.10-1.34), years in San Francisco (OR, 1.06 per year; 95% CI, 1.00-1.14), first injected by a sex partner (OR, 4.06; 95% CI, 1.74-9.52), injected daily (OR, 3.85; 95% CI, 2.07-7.17), ever borrowed a needle (OR, 2.56; 95% CI, 1.18-5.53), bleached last time a needle was borrowed (OR, 0.50; 95% CI, 0.24-1.02), snorted or smoked drugs in the prior year (OR, 0.48; 95% CI, 0.26-0.89), and injected by someone else in the prior month (OR, 0.50; 95% CI, 0.25-0.99). In the prior month, 88% used at least 1 of several needle exchange venues, and 32% borrowed a needle. We conclude that anti-HCV prevalence is lower than in previous studies of older IDUs, but 11% incidence implies high risk of HCV infection in a long injecting career. Despite access to sterile needles, borrowing of needles persisted.

Adolescent↗
PubMed2000

Adherence to isoniazid prophylaxis in the homeless: a randomized controlled trial.

OBJECTIVES: To test 2 interventions to improve adherence to isoniazid preventive therapy for tuberculosis in homeless adults. We compared (1) biweekly directly observed preventive therapy using a $5 monetary incentive and (2) biweekly directly observed preventive therapy using a peer health adviser, with (3) usual care at the tuberculosis clinic. METHODS: Randomized controlled trial in tuberculosis-infected homeless adults. Outcomes were completion of 6 months of isoniazid treatment and number of months of isoniazid dispensed. RESULTS: A total of 118 subjects were randomized to the 3 arms of the study. Completion in the monetary incentive arm was significantly better than in the peer health adviser arm (P = .01) and the usual care arm (P = .04), by log-rank test. Overall, 19 subjects (44%) in the monetary incentive arm completed preventive therapy compared with 7 (19%) in the peer health adviser arm (P = .02) and 10 (26%) in the usual care arm (P = .11). The median number of months of isoniazid dispensed was 5 in the monetary incentive arm vs 2 months in the peer health adviser arm (P = .005) and 2 months in the usual care arm (P = .04). In multivariate analysis, independent predictors of completion were being in the monetary incentive arm (odds ratio, 2.57; 95% CI, 1.11-5.94) and residence in a hotel or other stable housing at entry into the study vs residence on the street or in a shelter at entry (odds ratio, 2.33; 95% CI, 1.00-5.47). CONCLUSIONS: A $5 biweekly cash incentive improved adherence to tuberculosis preventive therapy compared with a peer intervention or usual care. Living in a hotel or apartment at the start of treatment also predicted the completion of therapy.

Adult↗
PubMed2000

Risk of hepatitis B infection among young injection drug users in San Francisco: opportunities for intervention.

OBJECTIVE: To compare the demographic characteristics and risk behaviors for hepatitis B infection among injection drug users younger than 30 years with those aged 30 or older and to evaluate participants' knowledge, attitudes, and experiences of infection, screening, and vaccination against hepatitis B virus. DESIGN: A systematic sample of injection drug users not currently in a treatment program were recruited and interviewed at needle exchange programs and community sites. PARTICIPANTS: 135 injection drug users younger than 30 years and 96 injection drug users aged 30 or older. RESULTS: Injection drug users younger than 30 were twice as likely as drug users aged 30 or older to report having shared needles in the past 30 days (36/135 [27%] vs 12/96 [13%]). Injection drug users younger than 30 were also twice as likely to report having had more than two sexual partners in the past 6 months (80/135 [59%] vs 29/96 [30%]). Although 88 of 135 (68%) young injection drug users reported having had contact with medical providers within the past 6 months only 13 of 135 (10%) had completed the hepatitis B vaccine series and only 16 of (13%) perceived themselves as being at high risk of becoming infected with the virus. CONCLUSION: Few young injection drug users have been immunized even though they have more frequent contact with medical providers and are at a higher risk for new hepatitis B infection than older drug users. Clinicians caring for young injection drug users and others at high risk of infection should provide education, screening, and vaccination to reduce an important source of hepatitis B infection.

Adult↗
PubMed2000

Tuberculosis in the homeless. A prospective study.

We set out to determine tuberculosis incidence and risk factors in the homeless population in San Francisco. We also examined the transmission of tuberculosis by molecular methods. We followed a cohort of 2,774 of the homeless first seen between 1990 and 1994. There were 25 incident cases during the period 1992 to 1996, or 270 per 100,000 per year (350/100,000 in African Americans, 450/100,000 in other nonwhites, 60/100,000 in whites). Ten cases were persons with seropositive HIV. Independent risk factors for tuberculosis were HIV infection, African American or other nonwhite ethnicity, positive tuberculin skin test (TST) results, age, and education; 60% of the cases had clustered patterns of restriction fragment length polymorphism, thought to represent recent transmission of infection with rapid progression to disease. Seventy-seven percent of African-American cases were clustered, and 88% of HIV-seropositive cases. The high rate of tuberculosis in the homeless was due to recent transmission in those HIV-positive and nonwhite. African Americans and other nonwhites may be at high risk for infection or rapid progression. Control measures in the homeless should include directly observed therapy and incentive approaches, treatment of latent tuberculous infection in those HIV-seropositive, and screening in hotels and shelters.

Adult↗
PubMed1999

A molecular epidemiologic analysis of tuberculosis trends in San Francisco, 1991-1997.

BACKGROUND: To decrease tuberculosis case rates and cases due to recent infection (clustered cases) in San Francisco, California, tuberculosis control measures were intensified beginning in 1991 by focusing on prevention of Mycobacterium tuberculosis transmission and on the use of preventive therapy. OBJECTIVE: To describe trends in rates of tuberculosis cases and clustered cases in San Francisco from 1991 through 1997. DESIGN: Population-based study. SETTING: San Francisco, California. PATIENTS: Persons with tuberculosis diagnosed between 1 January 1991 and 31 December 1997. MEASUREMENTS: DNA fingerprinting was performed. During sequential 1-year intervals, changes in annual case rates per 100,000 persons for all cases, clustered cases (cases with M. tuberculosis isolates having identical fingerprint patterns), and cases in specific subgroups with high rates of clustering (persons born in the United States and HIV-infected persons) were examined. RESULTS: Annual tuberculosis case rates peaked at 51.2 cases per 100,000 persons in 1992 and decreased significantly thereafter to 29.8 cases per 100,000 persons in 1997 (P < 0.001). The rate of clustered cases decreased significantly over time in the entire study sample (from 10.4 cases per 100,000 persons in 1991 to 3.8 cases per 100,000 persons in 1997 [P < 0.001]), in persons born in the United States (P < 0.001), and in HIV-infected persons (P = 0.003). CONCLUSIONS: The rates of tuberculosis cases and clustered tuberculosis cases decreased both overall and among persons in high-risk groups. This occurred in a period during which tuberculosis control measures were intensified.

AIDS-Related Opportunistic Infections↗
PubMed1999

Street talk: knowledge and attitudes about tuberculosis and tuberculosis control among homeless adults.

OBJECTIVES: To measure knowledge and perceived susceptibility to tuberculosis among homeless adults in San Francisco and attitudes toward control measures used to improve adherence to treatment for tuberculosis. DESIGN: A cross-sectional survey via interview of homeless shelter residents was done at five shelters. RESULTS: Of 292 persons interviewed, 21.6% reported a positive skin test, and 57.1% of the positives had received preventive therapy. Over 60% had misconceptions about transmission, in particular confusion with transmission of the human immunodeficiency virus (HIV). Knowledge of skin testing procedures and symptoms was generally good, and most reported health care providers as the main source of information. Over half reported concern about catching tuberculosis and over 80% favored controls to ensure adherence, in particular directly observed therapy. Higher TB knowledge score (P = 0.0155) and male sex (P = 0.0357) were associated with a favorable attitude toward directly observed therapy. CONCLUSIONS: Health care providers should expand educational messages beyond skin testing. Greater knowledge about tuberculosis may increase acceptance of control measures. Targeted education plus social norms favoring completion of therapy may improve screening and treatment outcomes in this population.

Adult↗
PubMed1998

Incidence of tuberculosis in injection drug users in San Francisco: impact of anergy.

Between 1990 and 1994, we conducted a prospective study in five methadone maintenance clinics in San Francisco to determine the rate of tuberculosis (TB) in injection drug users, including those who were anergic. Of the 1,745 persons seen in the clinics, 1,109 completed an evaluation that included skin testing with tuberculin and at least two other antigens (mumps, tetanus, and/or Candida), as well as HIV testing. All persons with a positive tuberculin skin test (TST) and anergic individuals who had radiographic evidence of tuberculous infection (i.e., calcified granulomas) were offered isoniazid (INH) preventive therapy. The median follow-up was 22.0 mo. There were 338 (30.5%) human immunodeficiency virus (HIV)-seropositive patients and 771 (69.5%) HIV-seronegative patients; 96 (28.0%) and 336 (44.0%), respectively, had positive TSTs. Of the HIV-seropositive subjects, 108 (31.9%) had no reaction to any of the three antigens, and were therefore classified as anergic. The rate of TB among the HIV-seropositive, TST-positive patients who did not take INH preventive therapy was 5.0 per 100 person-yr, compared with 0.4 per 100 person-yr among the HIV-seronegative, TST-positive patients (p = 0.007). There were no cases of TB among the anergic subjects. These data indicate that INH preventive therapy is not routinely indicated in anergic, HIV-seropostive patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Differences in contributing factors to tuberculosis incidence in U.S. -born and foreign-born persons.

To determine the factors contributing to tuberculosis incidence in the U.S.-born and foreign-born populations in San Francisco, California, and to assess the effectiveness of tuberculosis control efforts in these populations, we performed a population-based molecular epidemiologic study using 367 patients with strains of Mycobacterium tuberculosis recently introduced into the city. IS6110-based and PGRS-based restriction fragment length polymorphism (RFLP) analyses were performed on M. tuberculosis isolates. Patients whose isolates had identical RFLP patterns were considered a cluster. Review of public health and medical records, plus patient interviews, were used to determine the likelihood of transmission between clustered patients. None of the 252 foreign-born cases was recently infected (within 2 yr) in the city. Nineteen (17%) of 115 U. S.-born cases occurred after recent infection in the city; only two were infected by a foreign-born patient. Disease from recent infection in the city involved either a source or a secondary case with human immunodeficiency virus (HIV) infection, homelessness, or drug abuse. Failure to identify contacts accounted for the majority of secondary cases. In San Francisco, disease from recent transmission of M. tuberculosis has been virtually eliminated from the foreign-born but not from the U.S.-born population. An intensification of contact tracing and screening activities among HIV-infected, homeless, and drug-abusing persons is needed to further control tuberculosis in the U.S.-born population. Elimination of tuberculosis in both the foreign-born and the U.S. -born populations will require widespread use of preventive therapy.

AIDS-Related Opportunistic Infections↗
PubMed1998

Cancer screening in homeless women: attitudes and behaviors.

Little is known about the use of cancer-screening services in homeless women and their attitudes about early detection programs. Face-to-face interviews were conducted with homeless women in San Francisco to determine rates of clinical breast exams, mammograms, and Pap smears. A total of 105 women were randomly selected from two homeless shelters. By self-report, 51 percent were current on clinical breast exams, 47 percent on mammograms, and 54 percent on Pap smears. These women had very positive attitudes toward receiving cancer-screening exams. In multivariate analyses, discussion about cancer prevention with a health care provider predicted current clinical breast exams and mammograms. More medical visits predicted being current on mammograms and Pap smears. Although homeless women represent a unique group of the urban poor, they are accessing cancer-screening exams at rates comparable to the general population.

Adult↗
PubMed1997

Sexual risk behavior and risk factors for HIV-1 seroconversion in homosexual men participating in the Tricontinental Seroconverter Study, 1982-1994.

Trends in sexual behavior associated with incident infection with human immunodeficiency virus (HIV) type 1 are described and a case-control study was conducted to examine risk factors for HIV seroconversion in homosexual men who became infected with HIV between 1982 and 1994 from four geographic sites: Amsterdam, the Netherlands; San Francisco, California; Vancouver, Canada; and Sydney, Australia. Changes in sexual behaviors were evaluated from cohort visits in the preseroconversion, seroconversion, and postseroconversion intervals and were further examined over three time periods: 1982-1984, 1985-1987, and 1988-1994. In a case-control study, sexual behaviors, substance use, and presence of sexually transmitted disease were compared between 345 HIV-positive cases and 345 seronegative controls matched by visit date and site. Receptive anal intercourse was the sexual behavior most highly associated with seroconversion. The odds ratio (OR) per receptive anal intercourse partner increase was 1.05 (95% confidence interval (CI) 1.02-1.09). To more carefully examine risk associated with receptive oral intercourse, analyses were done in a subgroup of men who reported no or one receptive anal intercourse partner. The risk (OR) associated with receptive oral intercourse partner increase was 1.05 (95% CI 1.0-1.11). In multivariate conditional logistic regression analyses, presence of sexually transmitted disease (OR = 3.39, 95% CI 1.95-5.91) and amphetamine use (OR = 2.55, 95% CI 1.26-5.15) were independently associated with seroconversion. Although the prevalence of major risk factors has decreased over time, the associations of these behaviors and HIV infection persist, suggesting that these risk behaviors remain important avenues for public health interventions.

Adult↗
PubMed1997

Who uses needle exchange? A study of injection drug users in treatment in San Francisco, 1989-1990.

We examined use of the San Francisco needle exchange program (NEP) by 1093 injection drug users (IDUs) recruited in methadone maintenance and out-patient detoxification programs in the first 2 years after the opening of the NEP in 1988. Thirty-one percent of IDUs had ever used the NEP. IDUs who were frequent injectors, homeless, and aware of their serostatus were more likely to use the NEP. To assess self-selection of IDUs at risk for seroconversion for using needle exchange, we calculated pre-needle exchange seroconversion rates. Among 385 IDUs seen twice, the HIV seroconversion rate was 0.38% per person year among subjects who never used needle exchange, but it was 9.34% per person year among those who later used needle exchange (p = 0.003). NEP attracted a subset of IDUs at very high risk for HIV infection. Among injectors who were interviewed before and after the opening of the needle exchanges in San Francisco, the number of sharing partners did not change among IDUs who attended or among IDUs who never attended the NEP. The NEP attracted a very-high-risk subgroup of IDUs, as measured by risk behavior and pre-needle exchange HIV-seroconversion rate. NEPs should be considered prime sites for behavior-change interventions.

Adolescent↗
PubMed1997

Associations of age, immunosuppression, and AIDS among homosexual men in the Tricontinental Seroconverter Study.

To characterize the associations of age, immunosuppression, and AIDS outcomes, we evaluated serial measures of CD4+ lymphocytes from 376 homosexual men with documented dates of HIV-1 seroconversion registered in the Tricontinental Seroconverter Study. Using regression models and adjusting for variation within individuals, we found no association between age and the number of CD4+ lymphocytes at seroconversion or with CD4+ lymphocyte decline after seroconversion. Men who developed opportunistic infections had fewer CD4+ lymphocytes at the time of diagnosis compared with men who developed AIDS-defining Kaposi's sarcoma. Older age was significantly associated with higher numbers of CD4+ lymphocytes in individuals diagnosed with AIDS-defining Kaposi's sarcoma but was not significant for individuals with opportunistic infections. Because older age shortens the latency period of Kaposi's sarcoma and does not affect the CD4+ lymphocyte loss, it results in higher CD4+ lymphocytes at the time of diagnosis. These findings suggest distinct biologic mechanisms for various AIDS manifestations, which is important for clinical decision making and health care planning.

AIDS-Related Opportunistic Infections↗
PubMed1997

Association between time homeless and perceived health status among the homeless in San Francisco.

The purpose of this study was to describe the perceived health of the homeless, and to measure the effect of time homeless on perceived health status, after controlling for sociodemographic characteristics and health conditions. The design was cross-sectional; the population was a representative sample of homeless in San Francisco, interviewed on health issues. Analysis of predictors of poor or fair health status was by logistic regression. In this sample of 2780 persons, 37.4% reported that their health status was poor or fair as compared to good or excellent. Reporting poor or fair health status was significantly associated with time homeless, after controlling for sociodemographic variables and health problems including results from screening for HIV and TB (OR = 1.49, 95% CI 1.24-1.79). Comparisons with data from the National Health Interview Survey (NHIS) showed poorer health status among the homeless persons in this study. Standardized morbidity ratios were highest for asthma; there was twice the number of homeless persons reporting asthma, in younger as well as older adults, as would be expected using NHIS rates. There was also an excess of arthritis, high blood pressure and diabetes in those age 18-44 as compared to adults in the Health Interview Survey. The time spent homeless remains associated with self-reported health status, after known contributors to poor health are controlled. Persons who have been homeless for longer periods of time may be the persons to whom health care interventions should be aimed.

Adult↗
PubMed1997

A city-wide outbreak of a multiple-drug-resistant strain of Mycobacterium tuberculosis in New York.

SETTING: Incident patients with active tuberculosis (TB) resistant to two or more drugs in New York City hospitals in 1992. OBJECTIVE: To examine the New York-wide distribution of Public Health Research Institute (PHRI) strain W of Mycobacterium tuberculosis, an extremely drug-resistant strain identified by a 17-band Southern hybridization pattern using IS6110, during the peak tuberculosis year of 1992. We also compared strain W with other strains frequently observed in New York. DESIGN: Blinded retrospective study of stored M. tuberculosis cultures by restriction fragment length polymorphism (RFLP) DNA fingerprinting, and chart review. RESULTS: We found 112 cultures with the strain W fingerprint and 8 variants in 21 hospitals among incident patients hospitalized in 1992. Almost all isolates were resistant to four first-line drugs and kanamycin. This single strain made up at least 22% of New York City multiple-drug-resistant (MDR) TB in 1992, far more than any other strain. Almost all W-strain cases were acquired immune deficiency syndrome (AIDS) patients. The cluster is the most drug-resistant cluster identified in New York and the largest IS6110 fingerprint cluster identified anywhere to date. CONCLUSION: Because recommended four-drug therapy will not sterilise this very resistant strain, there was a city-wide nosocomial outbreak of W-strain TB in the early 1990s among New York AIDS patients. Other frequently seen strains were either also very resistant, or, surprisingly, pansusceptible. Individual MDR strains can be spread widely in situations where AIDS and TB are both common.

Adult↗