John S. Atkinson

Centrality measures for disease transmission networks

Abstract This paper addresses the issue of the applicability of various network measures (provided by analysis programs such as UCINET) for the analysis of a disease transmission network. A simulation was conducted to estimate HIV transmission probabilities within an empirical network of cocaine injectors. The results of the simulation were then used as a criterion to evaluate network measures of disease vulnerability and infectivity. The analysis concludes that, for the type of disease transmission network studied, relatively simple ego-network-based network measures can be adequate to the measurement of vulnerability to disease and infectivity.

Sex, Drugs, Violence, and HIV Status Among Male-to-Female Transgender Persons in Houston, Texas

SUMMARY To inform the Community Planning Group (Houston, Texas) in setting HIV-prevention priorities, risk behavior surveys were completed by 67 male-to-female (MtF) transgender persons. By self-identification, 58% were preoperative and 48% were self-described heterosexual women. We found this small sample of male-to-female transgender individuals to have high rates of HIV infection, and high prevalence of risky behaviors, intimate partner violence, and suicidal ideation. Twenty-seven percent were infected with HIV. Barriers were seldom used during oral sex and used less than half the time for anal sex with either primary or casual partners. Nearly one-third of the sample reported use of methamphetamines, amyl nitrite or LSD and 40% reported crack or cocaine use. Intimate partner violence and forced sex were reported by 50% and 25%, respectively. Suicidal ideation was reported by 16% in the last 30 days; lifetime suicidal ideation was 60%.

Hiv seroPrevalence in a saMPle of tanzanian intravenous drug users

Injection drug use has recently emerged in sub-Saharan Africa. The purpose of this study was to assess the factors associated with increased risk of testing HIV-positive in a sample of injection drug users (IDUs) in Dar es Salaam, Tanzania. Participants were recruited by a trained outreach worker or were referred by IDUs who had completed the study. Blood specimens and self-reported socioeconomic and behavioral data were collected from 315 male and 219 female IDUs. Data were analyzed using univariate odds ratios and multivariate logistic regression modeling. Forty-two percent of the sample tested HIV-positive. Several socioeconomic, injection, and sexual factors were found to be associated with increased odds of testing HIV-positive. Multivariate analysis showed that having had sex more than 81 times in past 30 days, earning less than 100,000 shillings (US

Spatial Bridging in a Network of Drug-Using Male Sex Workers

76) in the past month, residency in Dar es Salaam for less than 5 years, and injecting for 3 years were independently associated with the greatest risk of infection. The rate of HIV infection in this sample of IDUs was found to be very high, suggesting that injection drug use may be a factor in the continuing epidemic in sub-Saharan Africa. The factors associated with increased risk of HIV infection suggest further research is needed on the needle use and sexual networks of IDUs.

Condom use self‐efficacy among U.S.‐ and foreign‐born Latinos in Texas

This study sought to determine whether drug-using male sex workers (MSWs) spatially bridge sexual networks across cities and to determine whether the behaviors of MSWs who bridge differ from the behaviors of those who do not. Data were collected from 42 MSWs in Houston, Texas, between May 2003 and February 2004. Spatial bridging was defined as having traded sex for money in another city before traveling to and trading in Houston. Cities bridged by MSWs were geographically plotted and were primarily located in the Gulf Coast and in Florida. Slightly less than half of MSWs were identified as spatially bridging from one city to another. A significantly higher proportion of MSWs who bridged cities were homosexual (55% vs. 23%) and HIV positive (31% vs. 5%). Those who bridged cities used marijuana and injected drugs more frequently and had significantly more male sex partners than MSWs who did not bridge cities. Despite the small sample size, this study found that many drug-using MSWs spatially bridge sexual networks in cities where they trade sex for money.

A cluster analysis of drug use and sexual HIV risks and their correlates in a sample of African-American crack cocaine smokers with HIV infection

The objective of this study was to assess the influence of condom use self‐efficacy on the reported condom use of Latinos. We conducted a rapid needs assessment study among U.S. and foreign‐born Latinos living in Houston, TX, to identify behavioral and psychosocial factors that influence their risk for HIV. Bilingual Latino interviewers conducted confidential face‐to‐face interviews with individuals living in apartment complexes or residential areas primarily populated by Latinos. A total of 152 participants completed the survey. Regression results indicate that education and gender influenced condom use self‐efficacy, which in turn influenced condom use in the last sexual encounter and with the primary sexual partner. However, gender and relationship risk were stronger predictors of condom use. Study results indicate that there are differences in condom use self‐efficacy and sexual risk behaviors between Latino men and women that need further exploration.

A COMPARISON OF PSYCHOSOCIAL BARRIERS AMONG WELFARE RECIPIENTS: IMPLICATIONS FOR DRUG TREATMENT

The purpose of this cross-sectional study was to classify a sample of HIV-seropositive African-American crack cocaine smokers into homogenous HIV drug use and sexual risk groups using a two step multivariate cluster analysis. Two hundred and fifty-eight crack cocaine smokers participated in the study. Cluster analysis revealed three distinct HIV risk groups. The highest risk group, the largest one, was characterized by frequent, daily crack use, multiple sex partners, trading sex, and inconsistent condom use. The consistent condom use group, the smallest group, was characterized by consistent condom use. The inconsistent condom use group, the second largest group, was distinguished by inconsistent condom use. Comparisons of the three HIV risk groups revealed that the highest risk group had a higher proportion of illegal sources of income, higher proportion of binged crack use, frequent, daily, alcohol use, same gender sex partners, and scored higher on depressive symptoms. Members of the consistent condom use group were more likely to have been HIV diagnosed for a shorter time, to have HIV serodiscordant casual sex partners, higher psychological motivation for condom use, and a lower frequency of vaginal sex. Members of the inconsistent condom use group were more likely to have a main sex partner, to be married, to be on public assistance, to know the HIV serostatus of their casual partner, and less likely to conceal their HIV serostatus. An alarming finding was that a large number of participants inconsistently used condoms with HIV serodiscordant sex partners. Interventions aiming to prevent the secondary spread of HIV infection in African-American crack cocaine smokers should take this variability in account and focus on the differences.

Characteristics, drug use, and sex partners of a sample of male sex workers

Implementation of Temporary Assistance for Needy Families (TANF) presents welfare recipients with time-limited benefits and work requirements. However, it is estimated that over 140,000 welfare recipients meet the DSM-IV criteria for “drug dependence”. In this study, samples of chronic drug using and non-drug using female TANF recipients were compared with regard to: current employment, psychological functioning, self-perceived employment skills, barriers to employment, and need for help in seeking employment. It was found that non-drug using study participants were significantly more likely to be employed and reported significantly higher self-perceived work skills than users. Chronic users reported significantly greater barriers to seeking employment. [Translations are provided in the International Abstracts Section of this issue.]

Differences in HIV Risk Behaviors by Gender in a Sample of Tanzanian Injection Drug Users

Some male sex workers (MSWs) are also engaging in a significant amount of illicit drug use and other high risk behavior. The purpose of this study was to examine demographic characteristics, HIV risk behaviors, and sex partner characteristics in a sample of MSW. Data were collected from 179 men who were trading sex for money in Houston, TX. In the past 30 days they reported an average of 56 male partners and 5 female partners. Of the 179 men, 152 had been tested for HIV and knew their status. Twenty-six percent of those tested had tested positive.

Mental health, drug use, and the transition from welfare to work.

This study investigated differences in drug use and sexual behaviors among from 237 male and 123 female heroin users in Dar es Salaam, Tanzania. Multivariate models of risk of needle sharing were estimated using multivariate logistic regression. Men were significantly older, more likely to inject only white heroin, share needles, and give or lend used needles to other injectors. Women were more likely to be living on the streets, have injected brown heroin, have had sex, have had a higher number of sex partners, and have used a condom with the most recent sex partner. Being male and earning less than US