同伴推动抽样法在吸毒人群基数估计中的应用

目的 探索用同伴推动抽样法(respondent-driven sampling,RDS)结合乘数法进行吸毒人群基数估计的可行性.方法 2008年,采用RDS招募东莞市社区吸毒人群进行面对面的问卷调查,获得样本所占接触强制戒毒所和美沙酮维持治疗(methadone maintenance treatment,MMT)门诊的比例,用RDS分析软件进行权重处理;结合当地强制戒毒所和MMT门诊的数据,估计吸毒人群基数.结果 经过15周,共招募303名吸毒者.以强制戒毒所为基础,估计东莞市吸毒人群为52 028(90% CI:35 196～81 590)人,是在册登记数的2.67(90% CI:1.81～4.19)倍;估计注射吸毒人群43 651(90% CI:29 529～68 454)人,占常住成年人口数的0.87%(90% CI:0.59%～1.36%).以MMT门诊为基础,估计东莞市吸毒人群为7 058(90% CI:3 555～13 162)人.结论 RDS结合乘数法对吸毒人群进行基数估计是可行的;但基于MMT门诊数据的估计结果可能会被低估,在应用时应注意选择合适的接触机构以及接触时间.     

受访者驱动抽样在人群规模估计中的应用进展

受访者驱动抽样（RDS）是一种专门针对隐匿人群的抽样方法,常用于跨性别者、暗娼、MSM等因耻辱感和法律制度的约束难以识别和接触的人群,并逐渐应用于一般人群。随着RDS的不断改进和完善,研究发现对RDS样本的社交网络规模赋予权重可以估计总体的情况及人群规模。本文对目前RDS在人群规模估计中的应用进展进行综述,为RDS的发展及使用该方法开展相关研究提供思路。     

用于难以接近人群的一种新的抽样方法：同伴推动抽样法（RDS）

本文介绍新近推出的一种针对难以接近人群的抽样方法-同伴推动抽样法（RDS）,对方法的理论要点、实际应用中的注意事项、用该法收集资料的分析以及方法的优缺点进行了讨论.     

北京市2017年同伴推动抽样法招募男男性行为人群抽样效果分析

目的 评价2017年北京市同伴推动抽样（RDS）法招募MSM人群的随机性和代表性。方法 采用RDS法招募北京市MSM人群进行面对面问卷调查和HIV检测。结果 共招募MSM 600人,其中种子14人,种子的网络规模中位数为10人,高于其他被招募的MSM,招募人数按轮次呈正偏态分布,第4轮招募人数最多。不同种子招募人数差异较大,招募链人数最多的为184人、113人和92人,5个种子的招募链人数不足10人,其中以2名大学生种子招募人数最少,仅各招募1人。主要人口学指标在5~9层达到平衡,各指标绘制的收敛图最终趋于平稳,瓶颈图除婚姻状况和文化程度中部分曲线收敛趋势不明显外,其他曲线最终趋于收敛。主要指标的同质系数除文化程度外均在1左右。HIV感染率为7.9%（95% CI：4.4%~11.4%）。结论 采用RDS法招募的MSM样本,主要人口学指标达到平衡,招募过程合理可控,在一定程度上可以代表北京市MSM人群。     

Implementation of respondent-driven sampling among female sex workers in Brazil, 2009

Female sex workers are known in Brazil and elsewhere in the world as one of the most-at-risk populations for risk of HIV infection, due to their social vulnerability and factors related to their work. However, the use of conventional sampling strategies in studies on most-at-risk subgroups for HIV is generally problematic, since such subgroups are small in size and are associated with stigmatized behaviors and/or illegal activities. In 1997, a probabilistic sampling technique was proposed for hard-to-reach populations, called Respondent-Driven Sampling (RDS). The method is considered a variant of chain sampling and allows the statistical estimation of target variables. This article describes some assumptions of RDS and all the implementation stages in a study of 2,523 female sex workers in 10 Brazilian cities. RDS proved appropriate for recruiting sex workers, allowing the selection of a probabilistic sample and the collection of previously missing information on this group in Brazil.     

Community mapping and respondent-driven sampling of gay and bisexual men's communities in Vancouver,Canada

Literature suggests formative research is vital for those using respondent-driven sampling (RDS) to study hidden populations of interest. However, few authors have described in detail how different qualitative methodologies can address the objectives of formative research for understanding the social network properties of the study population, selecting seeds and adapting survey logistics to best fit the population. In this paper we describe the use of community mapping exercises as a tool within focus groups to collect data on social and sexual network characteristics of gay and bisexual men in the metropolitan area of Vancouver, Canada. Three key themes emerged from analysing community maps along with other formative research data: (1) connections between physical spaces and social networks of gay and bisexual men, (2) diversity in communities and (3) substance use linked to formation of sub-communities. We discuss how these themes informed the planning and operations of a longitudinal epidemiological cohort study recruited by RDS. We argue that using community mapping within formative research is a valuable qualitative tool for characterising network structures of a diverse and differentiated population of gay and bisexual men in a highly developed urban setting.     

Utilization of respondent-driven sampling among a population of child workers in the diamond-mining sector of Sierra Leone

Abstract

This article describes the implementation of respondent driven sampling (RDS) in a study conducted in Kono District, Sierra Leone. RDS was used to identify children, under the age of 18 years old, working in the diamond sector of Sierra Leone. This includes children working directly as diamond miners as well as children working in the informal sector connected to the diamond field. The article seeks to postulate that RDS is a suitable method for a rapid approach to a population that is unidentified in size and demonstrate how RDS can reach a study population within a limited period.     

Assessing differences in groups randomized by recruitment chain in a respondent-driven sample of Seattle-area injection drug users

PurposeRespondent-driven sampling (RDS) is a form of peer-based study recruitment and analysis that incorporates features designed to limit and adjust for biases in traditional snowball sampling. It is being widely used in studies of hidden populations. We report an empirical evaluation of RDS's consistency and variability, comparing groups recruited contemporaneously, by identical methods and using identical survey instruments.MethodsWe randomized recruitment chains from the RDS-based 2012 National HIV Behavioral Surveillance survey of injection drug users in the Seattle area into two groups and compared them in terms of sociodemographic characteristics, drug-associated risk behaviors, sexual risk behaviors, human immunodeficiency virus (HIV) status and HIV testing frequency.ResultsThe two groups differed in five of the 18 variables examined (P ≤ .001): race (e.g., 60% white vs. 47%), gender (52% male vs. 67%), area of residence (32% downtown Seattle vs. 44%), an HIV test in the previous 12 months (51% vs. 38%). The difference in serologic HIV status was particularly pronounced (4% positive vs. 18%). In four further randomizations, differences in one to five variables attained this level of significance, although the specific variables involved differed.ConclusionsWe found some material differences between the randomized groups. Although the variability of the present study was less than has been reported in serial RDS surveys, these findings indicate caution in the interpretation of RDS results.     

应用受访者驱动抽样估计青岛市男男性行为者人群规模

目的  探索受访者驱动抽样(respondent-driven sampling, RDS)在男男性行为者(men who have sex with men, MSM)人群规模估计中的应用经验并估计青岛市MSM人群规模, 为青岛市艾滋病疫情估计和资源分配提供参考。方法  采用RDS于2022年8-10月招募青岛市MSM参与调查, 收集一般人口学特征及社交网络规模信息。采用RDS Analyst 0.72软件评估RDS招募效果, 通过定性访谈了解青岛市MSM人群参与调查的意愿及其对激励措施的态度, 利用连续抽样人群规模估计法估计青岛市MSM人群规模。结果  共招募671人参与研究, 其中种子10名, 种子所在招募链的人数均>20人, 招募轮次为4~14轮不等。研究对象的年龄组、婚姻状况、受教育程度及户籍地构成在第5~10轮达到均衡, 人口学特征的同质性系数均接近1。10名访谈对象均表示无论是否有激励措施都愿意参与此类调查。连续抽样人群规模估计法基于研究对象自我报告的社交网络规模及基于可见度估计的青岛市MSM人数为分别为80 405~93 410人和69 284~80 236人, 占青岛市成年男性人口的比例分别为1.88%~2.19%和1.62%~1.88%。结论  RDS在MSM人群的招募效果较好, 应用基于RDS的连续抽样人群规模估计法估计的青岛市MSM占当地成年男性人口的比例为1.62%~2.19%。     

采用同伴推动抽样法在重庆市男男性行为人群中开展HIV流行病学调查

目的 了解重庆市男男性行为(MSM)人群HIV的感染状况和相关危险因素,并探索同伴推动抽样方法(RDS)的可行性.方法 在前期定性调查的基础上,采用RDS对MSM人群进行抽样,用标准化问卷收集行为学信息并采集血液样本进行HIV和梅毒的血清学检测,采用RDSAT软件对数据进行权重处理并用SPSS软件进行单因素分析,NETDRAW软件作网络招募图.结果 经RDSAT软件调整后,在617名招募者中,HIV和梅毒的感染率分别为16.8%和10.9%.其中20～29岁组占73.0%,72.9%是本地人,83.4%未婚,学生的构成比最高占24.6%.最近半年83.4%的调查者有肛交行为,54.0%的人有无保护性肛交性行为.梅毒阳性与HIV感染状况密切相关.结论 重庆市MSM人群的HIV感染率处于较高水平;在重庆市MSM人群较活跃的地区RDS方法是简便可行的,相对于滚雪球法可招募到更多不常去"同志场所"的目标人群.     

采用同伴推动抽样法在重庆市男男性行为人群中开展HIV流行病学调查

目的 了解重庆市男男性行为(MSM)人群HIV的感染状况和相关危险因素,并探索同伴推动抽样方法(RDS)的可行性.方法 在前期定性调查的基础上,采用RDS对MSM人群进行抽样,用标准化问卷收集行为学信息并采集血液样本进行HIV和梅毒的血清学检测,采用RDSAT软件对数据进行权重处理并用SPSS软件进行单因素分析,NETDRAW软件作网络招募图.结果 经RDSAT软件调整后,在617名招募者中,HIV和梅毒的感染率分别为16.8%和10.9%.其中20～29岁组占73.0%,72.9%是本地人,83.4%未婚,学生的构成比最高占24.6%.最近半年83.4%的调查者有肛交行为,54.0%的人有无保护性肛交性行为.梅毒阳性与HIV感染状况密切相关.结论 重庆市MSM人群的HIV感染率处于较高水平;在重庆市MSM人群较活跃的地区RDS方法是简便可行的,相对于滚雪球法可招募到更多不常去"同志场所"的目标人群.     

Using respondent-driven sampling (RDS) to recruit illegal poly-substance users in Cape Town,South Africa: implications and future directions

Background

South Africa continues to witness an increase in illicit poly-substance use, although a precise measurement continues to be compounded by difficulties in accessing users. In a pilot attempt to use respondent-driven sampling (RDS)—a chain referral sampling method used to access populations of individuals who are ‘hard-to-reach’—this article documents the feasibility of the method as recorded in a simultaneously run, multisite, poly-substance study in Cape Town. Here we aim to a) document the piloting of RDS among poly-substance users in the three socio-economic disparate communities targeted; b) briefly document the results; and c) review the utility of RDS as a research tool.

Methods

Three cross-sectional surveys using standard RDS procedures were used to recruit active poly-substance users and were concurrently deployed in three sites. Formative research was initially conducted to assess the feasibility of the survey. To determine whether RDS could be used to successfully recruit poly-substance users, social network characteristics, such as network size was determined.

Results

A 42.5 % coupon return rate was recorded in total from 12 initial seeds. There were vast differences in the recruitment chains of individual seeds—two generated more than 90 recruits, and 2 of the 10 recruitment chains showing a length of more than 10 waves. Findings include evidence of the use of 3 or more substances in all three sites, high levels of unemployment among users, with more than a third of participants in two sites reporting arrest for drug use in the past 12 months.

Conclusions

Our results indicate that RDS was a feasible and acceptable sampling method for recruiting participants who may not otherwise be accessible. Future studies can use RDS to recruit such cohorts, and the method could form part of broader efforts to document vulnerable populations.

     

The role of rural communities in the recruitment and retention of women physicians

ABSTRACT

Rural communities in the United States have a shortage of primary care physicians. Women physicians are more likely than male physicians to choose primary care specialties but less likely to locate in rural areas. With an increasing proportion of women physicians, it is important to understand community characteristics that encourage their recruitment and retention. This qualitative study explored community characteristics that influenced successful rural practice. We conducted telephone interviews with 25 women family physicians in rural practice in the United States in 2012. Interviews continued until saturation of themes was reached. Data were analyzed using immersion and crystallization. Community themes associated with successful rural practice included: fit with the community; spouse/partner fit with the community; relationships with individuals; and relationships with the community. Family ties, training experience within the community, social networks, and investment in the community were positive factors, while political/cultural differences were negative. Community integration arose from compatibility between the physicians’ goals and community characteristics, opportunities for a spouse/partner, friendships, and a feeling of community purpose. This information can be used by rural communities to recruit and retain physicians, and by physicians, medical students, and those who advise them to promote successful rural practice.     

Evaluation of charcoal sampling tubes.

The effectiveness of MSA charcoal tubes and those constructed by the USAF Environmental Health Laboratory were statistically compared. No significant differences were noted. Also, tube recovery efficiencies were determined for 10 different solvents for which there was no or limited data. The effects of moisture on gravimetric analysis are presented.