Monday, October 31, 2011


HIV Risk Behaviours and their Relationship to Intimate Partner Violence (IPV) Among Men Who Have Multiple Female Sexual Partners in Cape Town, South Africa

Authors: Townsend, Loraine1; Jewkes, Rachel2; Mathews, Catherine3; Johnston, Lisa4; Flisher, Alan5; Zembe, Yanga3; Chopra, Mickey6

Source: AIDS and Behavior, Volume 15, Number 1, January 2011 , pp. 132-141(10)

Publisher: Springer


HIV/AIDS and intimate partner violence (IPV) are growing public health concerns in South Africa. Knowledge about adult men's perpetration of IPV and links between HIV risk behaviours and IPV is limited. Respondent driven sampling was used to recruit men who have multiple concurrent female sexual partners. Forty-one percent of the 428 recruited men had perpetrated IPV. Inconsistent condom use was associated with physical IPV; experiencing a symptom of a sexually transmitted infection and engaging in transactional sex were associated with physical and sexual IPV; problem alcohol use was associated with physical, and any IPV, but not sexual IPV; having five or more partners was associated with sexual IPV; perceptions of partners' infidelity were associated with physical and any IPV. HIV risk reduction interventions among men, especially those with multiple female sex partners, should incorporate strategies to change the underlying construction of masculinity that combines the anti-social and risky behaviours of IPV perpetration, inconsistent condom use, transactional sex and heavy alcohol consumption.

Keywords: Concurrent sexual partnerships; HIV prevention; High risk heterosexual men; Intimate partner violence; Respondent driven sampling; South Africa

Document Type: Research article

DOI: 10.1007/s10461-010-9680-5

Affiliations: 1: Health Systems Research Unit, Medical Research Council, P.O. Box 19070, Tygerberg 7505, Cape Town, South Africa, Email: 2: Gender and Health Research Unit, Medical Research Council, Pretoria, South Africa 3: Health Systems Research Unit, Medical Research Council, P.O. Box 19070, Tygerberg 7505, Cape Town, South Africa 4: School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA 5: Division of Child and Adolescent Psychiatry and Adolescent Health Research Unit, University of Cape Town, Cape Town, South Africa 6: United Nations Childrens Fund, New York, NY, USA

Publication date: 2011-01-01

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Yanga Zembe1, Loraine Townsend1, Cathy Mathews1, Mickey Chopra1, Anna
Mia Ekstrom2, Anna Thorson2, Susanne Stromdahl2, Heidi O’Bra3
1 Medical Research Council, Cape Town, South Africa
2 IHCAR, Karolinska Institute, Sweden
3 US Centers for Disease Control and Prevention/Global AIDS Program,
Pretoria, South Africa.

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The sensitivity of respondent-driven samplingXin Lu1, Linus Bengtsson2, Tom Britton3, Martin Camitz4, Beom Jun Kim5, Anna Thorson6, Fredrik Liljeros7Article first published online: 18 JUL 2011

DOI: 10.1111/j.1467-985X.2011.00711.x

Keywords:Directed network;Hidden population;Network;Respondent-driven sampling;Sampling;Sensitivity

Summary. Researchers in many scientific fields make inferences from individuals to larger groups. For many groups, however, there is no list of members from which to draw a random sample. Respondent-driven sampling (RDS) is a relatively new sampling methodology that circumvents this difficulty by using the social networks of the groups under study. The RDS method has been shown to provide unbiased estimates of population proportions given certain conditions. The method is now widely used in human immunodeficiency virus related studies among high risk populations globally. We test the RDS methodology by simulating RDS studies on the social networks of a large Lesbian, gay, bisexual and transgender Web community. The robustness of the RDS method is tested by violating, one by one, the conditions under which the method provides unbiased estimates. Simulations indicate that the bias is large if networks are directed or respondents choose to invite people on the basis of characteristics that are correlated with the study outcomes. The bias and variance increase if participants invite close as opposed to more distant friends whereas sampling in denser networks sharply reduces variance. However, the RDS method shows strong resistance to sampling without replacement, low response rates and certain errors in the participants’ reporting of their network sizes, as well as the selection criteria of seeds. The effects of network structure and the number of seeds and coupons are also discussed.

A novel application of respondent-driven sampling to evaluate effectiveness of a multi-level intervention using a cluster randomized trial: design of the DOST trial

S.S. Solomon1, S.H. Mehta2, F. Sifakis2, A.K. Srikrishnan1, S. Solomon1, D.D. Celentano2

1YRG Centre for AIDS Research and Education, Chennai, India, 2Johns Hopkins Bloomberg School of Public Health, Baltimore, United States

The impact of voluntary, counseling and testing (VCT) on risk-behavior and linkage to care is well established. Despite widespread availability in India (>1000 VCT centers), utilization among most-at-risk-populations (e.g., men who have sex with men [MSM]) remains low. We propose a novel application of respondent-driven sampling (RDS) to implement and evaluate the effectiveness of multi-level intervention to increase VCT utilization among MSM in south India using a cluster-randomized trial design.

We aim to evaluate the effectiveness of gay-friendly men's wellness centers (DOST Centers) on behavior change at the community-, network- and individual-levels in south India. Key challenges in the conduct of cluster-randomized trials are: 1) ensuring generalizability of the study population; 2) prevention of overlap between intervention and control clusters (contamination); and 3) evaluating impact at multiple levels.

We propose to leverage an established sampling strategy for hidden populations (RDS) to address these challenges. First, cross-sectional RDS surveys will be conducted in intervention and control communities prior to and 2 years after the establishment of DOST centers to assess community-level effectiveness of the intervention. Through weighting, RDS estimates can approximate underlying population estimates. Second, we will use RDS network information from the baseline RDS to identify discrete communities for randomization and disseminate information on DOST centers. Running concurrent RDS samples will allow us to identify/eliminate overlap in real time; disseminating information through discrete networks will optimize network relationships. Third, the evaluation RDS will allow evaluation of network-level impact using RDS process indicators and individual-level impact by comparison of participants who did and did not visit DOST centers in intervention communities.

We propose this novel application of RDS to address key challenges in the implementation of cluster-randomized trials and evaluation of intervention effectiveness. With increasing focus on implementation science, the DOST trial design can easily be adapted to other settings/populations.

Possible increase in HIV and syphilis prevalence among men who have sex with men in Guangzhou, China: results from a respondent-driven sampling survey.

Zhong F, Lin P, Xu H, Wang Y, Wang M, He Q, Fan L, Li Y, Wen F, Liang Y, Raymond HF, Zhao J.
SourceGuangzhou Municipal Center for Disease Control and Prevention, 510080, Guangzhou, China.

A respondent-driven sampling survey was conducted to investigate HIV related serological and behavioral characteristics of men who have sex with men (MSM) in Guangzhou, China, and to identify associated factors potentially driving the epidemic. Respondent-Driven Sampling Analysis Tool and SPSS were used to generate adjusted estimates and to explore associated factors. Three hundred seventy-nine eligible participants were recruited. The adjusted prevalence of HIV and current syphilis infection are 5.2% and 17.5% respectively. 60.3% have unprotected anal sex in the past 6 months. Unprotected anal sex, having receptive anal sex and current syphilis infection are significant factors associated with HIV infection. The potential for a rapid rise of HIV and syphilis infections among MSM in Guangzhou exists. Targeted interventions with voluntary counseling and testing (VCT) and sexually transmitted infection (STI) services are needed to address the epidemic, with a focus on such subgroups as those of with current syphilis, and non-official Guangzhou residence status.

Respondent-driven sampling to recruit MDMA users: A methodological assessment.

Drug and Alcohol Dependence 78(2):147-157, May 2005. Jichuan Wang, Robert G. Carlson, Russel S. Falck, Harvey A. Siegal, Ahmmed Rahman, and Linna Li.

Recruiting more representative samples of illicit drug users is a continuing challenge in substance abuse research. Respondent-driven sampling (RDS), a new form of chain-referral sampling, is designed to eliminate the bias caused by the non-random selection of the initial recruits and reduce other sources of bias, such as bias due to voluntarism and masking, that are usually associated with regular chain-referral sampling. This study assessed the application of RDS among young adult users of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") and found that the sample compositions converged to equilibrium within a limited number of recruitment waves, independent of the characteristics of the initial "seed" recruits. The sample compositions approximated the theoretical equilibrium compositions, and were not significantly different from the estimated population compositions, except that white respondents were over-sampled and black respondents were under-sampled. The effect of voluntarism and masking on the sampling process was not significant. Though identifying productive seeds and improving the referral rate are significant challenges when implementing RDS, the results show that RDS is a flexible and robust sampling method with the potential to be widely used in studies of illicit drug-using populations.

NIAAA Glossary Terms: illicit drug, AOD user, sample selection, sampling bias, research issue, MDMA, racial differences, White, Black, intervention referral, human study

Respondent-driven sampling on the Thailand-Cambodia border. I. Can malaria cases be contained in mobile migrant workers?

Submitted by patrick sampao on May 11, 2011 - 12:33
Tags: Cambodiamalariamigrant workersThailand
Author(s): Amnat Khamsiriwatchara, Piyaporn Wangroongsarb, Julie Thwing, James Eliades, Wichai Satimai, Charles Delacollette, Jaranit Kaewkungwal
Reference: Malaria Journal 2011, 10:120 (10 May 2011)
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Reliable information on mobility patterns of migrants is a crucial part of the strategy to contain the spread of artemisinin-resistant malaria parasites in South-East Asia, and may also be helpful to efforts to address other public health problems for migrants and members of host communities. In order to limit the spread of malarial drug resistance, the malaria prevention and control programme will need to devise strategies to reach cross-border and mobile migrant populations.

The Respondent-driven sampling (RDS) method was used to survey migrant workers from Cambodia and Myanmar, both registered and undocumented, in three Thai provinces on the Thailand-Cambodia border in close proximity to areas with documented artemisinin-resistant malaria parasites. 1,719 participants (828 Cambodian and 891 Myanmar migrants) were recruited. Subpopulations of migrant workers were analysed using the Thailand Ministry of Health classification based on length of residence in Thailand of greater than six months (long-term, or M1) or less than six months (short-term, or M2). Key information collected on the structured questionnaire included patterns of mobility and migration, demographic characteristics, treatment-seeking behaviours, and knowledge, perceptions, and practices about malaria.

Workers from Cambodia came from provinces across Cambodia, and 22% of Cambodian M1 and 72% of Cambodian M2 migrants had been in Cambodia in the last three months. Less than 6% returned with a frequency of greater than once per month. Of migrants from Cambodia, 32% of M1 and 68% of M2 were planning to return, and named provinces across Cambodia as their likely next destinations. Most workers from Myanmar came from Mon state (86%), had never returned to Myanmar (85%), and only 4% stated plans to return.

Information on migratory patterns of migrants from Myanmar and Cambodia along the malaria endemic Thailand-Cambodian border within the artemisinin resistance containment zone will help target health interventions, including treatment follow-up and surveillance.

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