The prevalence of problem drug misuse in a rural county of England

Previous capture-recapture studies have estimated the prevalence of problem drug misuse in urban areas. This study estimates the prevalence in a rural county, Norfolk, using data from four sources: drug treatment agencies, probation, the arrest referral service, and police (drug-related crime with/without acquisitive crime). Careful consideration was given to methods of matching datasets and sensitivity analyses involved altering matching rules and postcode criteria. Whilst it is recognised that acquisitive crime is often related to drug use, this is the first capture-recapture study to incorporate acquisitive crime data. In further sensitivity analyses the proportion of acquisitive crime assumed to be drug-related was varied from 25-60%. The main analysis provided an estimated prevalence of problem drug use in Norfolk of 2.05% (95% confidence interval: 1.66%-2.56%) for ages 15-54 years, considerably higher than the 1.1% currently suggested for the UK. Sensitivity analyses based on varied matching and postcode criteria produced estimates ranging from 2.41%-3.37%, suggesting our estimate may be conservative. Sensitivity analyses assuming that 25-60% of acquisitive crimes were drug-related, produced estimates ranging from 2.02% to 5.73%, further supporting our main analysis. In conclusion, this study provides evidence that problem drug misuse is more prevalent in this rural population than previously thought.     

A comparison and critique of historical and current exposure assessment methods for beryllium: implications for evaluating risk of chronic beryllium disease

The primary beryllium industry has generated a large amount of data on airborne beryllium concentrations that has been used to characterize exposure by task-specific activities, job category, individual worker, and processing area using a variety of methods. These methods have included high-volume breathing zone sampling, high-volume process sampling, high- and low-volume respirable and area sampling, real-time monitoring, and personal sampling. Many of the beryllium studies have used these air sampling methods to assess inhalation exposure and chronic beryllium disease (CBD) risk to beryllium; however, available data do not show a consistent dose-response relationship between airborne concentrations of beryllium and the incidence of CBD. In this article, we describe the air sampling and exposure assessment methods that have been used, review the studies that have estimated worker exposures, discuss the uncertainties associated with the level of beryllium for which these studies have reported an increased risk of CBD, and identify future investigative exposure assessment strategies. Our evaluation indicated that studies of beryllium workers are often not directly comparable because they (1) used a variety of exposure assessment methods that are not necessarily representative of individual worker exposures, (2) rarely considered respirator use, and (3) have not evaluated changes in work practices. It appears that the current exposure metric for beryllium, total beryllium mass, may not be an appropriate measurement to predict the risk of CBD. Other exposure metrics such as mass of respirable particles, chemical form, and particle surface chemistry may be more related to the prevalence of CBD than total mass of airborne beryllium mass. In addition, assessing beryllium exposure by all routes of exposure (e.g., inhalation, dermal uptake, and ingestion) rather than only inhalation exposure in future studies may prove useful.     

Main reasons for non-use of illicit drugs by young population exposed to risk situations

OBJECTIVE: Although there are many studies on risk factors for drug use, little has been known about the reasons that prevent people away from drug use. The aim of this study was to identify the reasons that would prevent low-income youngsters against psychotropic drug experimentation and use, even when living in a drug dealing environment. METHODS: A qualitative study was carried out in an intentional sample selected according to a set of criteria. Sixty-two youngsters, aged between 16 and 24 years, from low-income families who have never used psychotropic drugs (32 subjects) or who were heavy drug users (30 subjects) were interviewed. Each interview lasted on average 110 minutes. RESULTS: Among non-users, access to information and a protective family structure were identified as major reasons from preventing youngster from drug use. Comprehensive information on the outcomes of drug use and affective bonds between parents and their children, assured by feelings of support and respect, seems to be important in helping them avoid drug use. The importance of these two factors as reasons to keep youngsters away from drugs is emphasized when their lack is mentioned and censured by drug users. CONCLUSIONS: The outlook of those who have never used drugs in their lifetime and their reasons should be considered in the development of drug prevention programs targeting low-income youngsters.     

Capture-recapture estimates of problem drug use and the use of simulation based confidence intervals in a stratified analysis

STUDY OBJECTIVE: To establish the prevalence of problem drug use in the 10 local authorities within the Metropolitan County of Greater Manchester between April 2000 and March 2001. SETTING AND PARTICIPANTS: Problem drug users aged 16-54 resident within Greater Manchester who attended community based statutory drug treatment agencies, were in contact with general practitioners, were assessed by arrest referral workers, were in contact with the probation service, or arrested under the Misuse of Drugs Act for offences involving possession of opioids, cocaine, or benzodiazepines. DESIGN: Multi-sample stratified capture-recapture analysis. Patterns of overlaps between data sources were modelled in a log-linear regression to estimate the hidden number of drug users within each of 60 area, age group, and gender strata. Simulation methods were used to generate 95% confidence intervals for the sums of the stratified estimates. MAIN RESULTS: The total number of problem drug users in Greater Manchester was estimated to be 19 255 giving a prevalence of problem drug use of 13.7 (95% CI 13.4 to 15.7) per 1000 population aged 16-54. The ratio of men to women was 3.5:1. The distribution of problem drug users varied across three age groups (16-24, 25-34, and 35-54) and varied between the 10 areas. CONCLUSIONS: Areas in close geographical proximity display different patterns of drug use in terms of prevalence rates and age and gender patterns. This has important implications, both for future planning of service provision and for the way in which the impact of drug misuse interventions are evaluated.     

Comparison of methods for estimating drug coverage for filariasis elimination, Leogane Commune, Haiti

In the global effort to eliminate lymphatic filariasis, annual mass treatments are conducted with diethylcarbamazine (DEC) or ivermectin, combined with albendazole. The success of this strategy depends on achieving high levels of drug coverage, which reduces the number of persons with circulating microfilariae so that transmission of the parasite is interrupted. Because resources are often limited, a simple, inexpensive, and reliable method to estimate drug coverage is needed. During the period December 2000 to February 2001, three methods were used to assess drug coverage in Leogane Commune, Haiti: a probability survey using a cluster sample design (n = 1421 persons); a distribution-point survey based on a convenience sample of houses near the distribution points (n = 4341 persons); and a survey based on a convenience sample of primary schools (n = 5036 children). The coverage estimations were 71.3% (95% CI 66.7-75.9), 73.6% (95% CI 70.1-77.0), and 77.8% (95% CI 73.5-82.1), respectively. Survey costs for the probability, distribution point, and school surveys were US$2217, US$979, and US$312, respectively. The 2 convenience sampling methods provided point estimates of drug coverage that were similar to those of the probability survey. These methods may have a role for monitoring drug treatment coverage between less frequent, but more costly, probability sample surveys.     

常用二阶段抽样方法的评价

目的评价在流行病学调查研究中,三种常用的二阶段抽样方法对估计总体参数产生的偏倚。方法在横断面调查的二阶段抽样中,常用的抽样方法有随机抽样、根据先验信息在中心位置抽样、以及方便抽样等。用SAS软件编程对三种抽样方法得到的各个样本资料进行区间估计以及估计95%可信区间包含总体均数的覆盖率,比较不同抽样方式的覆盖率差异。结果分别给出了在三种抽样方法下得到的区间估计包含总体均数的覆盖率。结论在ICC(组内相关系数)比较小时,根据先验信息在中心位置抽样与随机抽样具有相似的效果。在这种情况下,可以选择根据先验信息在中心位置抽样或随机抽样的方法。大多数情况下,方便抽样的偏倚最大,这种方法在实际中不建议使用。     

Indirect prevalence estimates of a national drug using population: The use of contact-recontact methods in Wales

The changing discourses of risk entail more than shifts in cosmologies of misfortune: they also embrace technical changes in risk surveillance. Public health medicine has sought estimates of drug-using populations to plan drug services and to interpret data on the prevalence of infectious diseases. Concealment of risk behaviours had led to technical advances in indirect methods of population estimation, one such method being that of contact-recontact, where the size of the hidden population (unknown to agencies) is estimated by modelling the dependency relationships (the overlaps) between different agenices lists of clients. This study demonstrates the use of contact-recontact methods for estimating the national prevalence of serious drug use, a procedure only previously attempted for city-wide populations of drug users. Three- and four-sample contact-recontact models have been used and log linear regression techniques have been applied to assess dependencies between datasets. Results from the modelling exercise provide an estimate for serious drug use in Wales in 1994 of 8384 people (95% C.I. 5307-11 407). This gives a rate per thousand population of 2.87 (95% C.I. 1.8-3.9) and 5.34 (95% C.I. 3.4-7.3) per thousand aged 15-55. Prevalence estimates are also provided for former Welsh counties by age and sex. Prevalence estimates for injecting drug use are provided for a smaller number of former counties in Wales. Methodological problems have been encountered (and variously addressed) in respect of varying agency definitions of clients, matching definitions and availability of datasets.     

Sampling and Recruitment in Multilevel Studies among Marginalized Urban Populations: The IMPACT Studies

Illicit drug use in urban settings is a major public health problem. A range of individual level factors are known to influence drug use and its consequences, and a number of recent studies have suggested that the neighborhood in which an individual lives may also play a role. However, studies seeking to identify neighborhood-level determinants of drug use, particularly among marginalized urban populations, need to overcome significant challenges, particularly in the area of sampling and recruitment. One key issue is defining functional neighborhoods that are relevant to local residents. Another arises from the need to sample a representative or even a diverse population when studying marginalized groups such as illicit drug users. These are common problems that raise particular challenges when both need to be addressed in the same study. For example, many sampling approaches for neighborhood-level studies have included some form of random sample of households, but this may systematically overlook marginalized populations. On the other hand, the sampling approaches commonly used in studies of hidden populations such as chain referral, snow ball, and more recently, respondent-driven sampling, typically expand beyond a geographic “neighborhood.” We describe the organization and rationale for the IMPACT Studies in New York City as a case illustration on how such issues may be addressed. Ompad, Galea, Fuller, Weiss, Beard, Chan, Edwards, and Vlahov are with the Center for Urban Epidemiologic Studies, New York Academy of Medicine, New York, NY, USA; Galea is with the Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA; Marshall is with the RAND Corporation, Santa Monica, CA, USA; Fuller and Vlahov are with the Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA.     

Secondary prevention: an approach to improve the German drug abuse prevention system

Drug prevention in Germany traditionally focuses on primary prevention programmes for children without any drug experience. Only a few programmes have been specifically developed for drug-taking youth, although especially children and adolescents at high risk for drug problems need intervention services which provide helpful support to reduce drug misuse. Empirical studies in two German cities show that prevention services are not available for the high-risk population of drug-taking youth. On an international level several projects are testing out new approaches for drug use prevention for at-risk youth. The primary goal of such secondary prevention programmes is to reduce the incidence and prevalence of drug use and abuse through early detection and intervention strategies. These programmes aim at preventing adolescents who are experimenting with drugs from progressing to misuse or addiction. Testing new prevention strategies to support drug-taking youth in Germany is likely to produce a valuable contribution to our knowledge of effective drug prevention.     

天津市青年学生男男性行为者新型毒品使用现状及影响因素分析

  目的  了解天津市青年学生男男性行为者(men who have sex with men,MSM)的基本特征、性行为情况以及新型毒品的使用情况,并探究使用新型毒品青年学生MSM的特征,为高校艾滋病防控相关政策制定提供参考依据。  方法  于2018年1月1日至12月31日,在天津市通过滚雪球抽样的方式在同性浴池、同性酒吧和社交软件等途径招募青年学生MSM。通过面对面访谈的方式与参与者沟通。通过调查问卷收集826名参与者基本人口学信息、性行为情况、新型毒品使用等信息。使用Logistic回归分析青年学生MSM中新型毒品使用者的特征。  结果  经实验室确证的HIV感染者32人,总体感染率为3.87%。其中新型毒品使用者为371人(44.92%)。Rush是使用率最高(98.65%)的新型毒品。在使用新型毒品的青年学生MSM中,306人(82.48%)使用过多种毒品,65人(17.52%)仅使用过一种毒品。多种毒品使用者的HIV感染率(16.92%)高于单一毒品使用者(4.57%)。年龄、首次性行为年龄、户籍、性取向、教育程度、性伴寻找方式、无保护性肛交和HIV检测史对青年学生MSM新型毒品使用影响均有统计学意义(OR值分别为3.70,5.51,0.51,0.60,4.64,0.40,0.52,1.98,2.29,P值均 < 0.05)。  结论  天津市青年学生男男性行为者中新型毒品使用率偏高。相关部门应加强高校禁毒防艾宣传,提高青年学生性健康意识,建立长效的HIV和毒品预防机制。     

Estimating the prevalence of drug misuse in Dundee, Scotland: an application of capture-recapture methods.

STUDY OBJECTIVES: To apply capture-recapture methods to provide an estimate of the prevalence of opiate and benzodiazepine misuse in Dundee, Scotland. DESIGN: A four sample capture-recapture method using data from both statutory and non-statutory data sources to estimate drug misuse prevalence in Dundee between January 1990 and December 1994. PARTICIPANTS: Users of benzodiazepines or opiates residing within Dundee. RESULTS: Altogether 855 drug misusers were identified from various sources within Dundee; many were identified from more than one source. Using this data, the estimated unknown population was 1702, giving a total population of 2557 (95% confidence interval (CI) 1974, 3458) who misuse benzodiazepines or opiates. This represents a prevalence of 28.8 (95% CI 22.3, 39.0) per thousand. CONCLUSIONS: Capture-recapture techniques can be applied to statutory and non-statutory agency data to produce an estimate of at least certain sections of the drug misusing population. However, it is important to recognise the limitations of this methodology and in future to seek to combine a range of approaches to the problem of estimating prevalence rather than sticking rigidly to any single approach.     

Bayesian methods for prevalence estimation from incomplete administrative lists

Many studies aimed at estimating prevalence use several administrative lists from different sources in an attempt to enumerate all persons affected with the health condition of interest. Each list is 'incomplete' in the sense that none of them enumerates all persons affected with the health condition. Further, because the lists are drawn from different administrative sources the probability of enumeration varies from list to list. The goal is to use information from the lists to estimate the total number of affected persons in the population, but with some accounting for the different but unknown probabilities of enumeration on each list. This paper presents a Bayesian method to estimate prevalence when the probability of enumeration varies from list to list. Data from a survey of children with spina bifida illustrate the methodology.     

遂宁市注射吸毒者综合干预模式效果评估

摘要：目的　评估遂宁市２００８－２０１２年注射吸毒者接受清洁针具交换为核心的综合干预效果。方法　采取
“方便样本法”和“滚雪球法”每年对２００名参加清洁针具交换注射吸毒者用统一制定的问卷进行面对面的
访谈式调查,调查结果用Ｅｐｉｄａｔａ３．０进行录入,ＳＰＳＳ１７．０进行描述性分析和χ
２ 检验。结果　２００８－２０１２
年遂宁市注射吸毒者对艾滋病知识的知晓率有持续升高趋势,从４１．５０％上升至９２．５０％,差异有统计学意
义（犘＜０．０１）。注射吸毒者最近一次共针率有持续下降趋势,从６２．１０％ 下降至２７．３０％,差异有统计学
意义（犘＝０．００２）。注射吸毒者最近一次以及最近一年与配偶、临时性伴、商业性伴发生性关系时安全套
使用率持续上升,差异均有统计学意义（犘＜０．０１）。结论　遂宁市注射吸毒者清洁针具交换为核心的综合
干预模式取得了较好的成效,应该继续坚持并完善这种综合干预模式。
关键词：吸毒者;清洁针具交换;干预模式;评估
中图分类号：Ｒ１８３．７　　文献标识码：Ａ　　文章编号：１００９ ６６３９ （２０１４）０５ ０４５７ ０４     

Heroin misuse and family medicine

Drug users are a heterogeneous group in terms of social class and background, personality, and patterns of drug use. They are often stereotyped by both the public and the health services and this can lead to obstruction of a successful doctor-patient relationship. The real problem lies not so much in detoxification but in the prevention of relapses and the maintenance of the patient in a drug-free condition. There has recently been a shift in emphasis away from drug treatment centres and hospital based treatment towards community care and family medicine. The role of the family practitioner is largely unexplored yet, rather than inspiring research, the increased contact between general practitioners and drug users has caused concern. This review concentrates on two related areas of study important for family practitioners in the management of drug misuse: the role of drug misuse in family membership and in parenthood. Families have been shown to play a role in the aetiology of drug abuse, but more important is their role in the maintenance of an individual's drug dependence. The family doctor is in an ideal position to recruit the family into the drug user's treatment. Although far fewer 'addicts' come to serious harm than is commonly believed, the risks extend also to the children born of narcotic dependent mothers. Family doctors, obstetricians and paediatricians must be aware of the particular problems for mother and child.     

Recruiting Injection Drug Users: A Three-Site Comparison of Results and Experiences with Respondent-Driven and Targeted Sampling Procedures

Several recent studies have utilized respondent-driven sampling (RDS) methods to survey hidden populations such as commercial sex-workers, men who have sex with men (MSM) and injection drug users (IDU). Few studies, however, have provided a direct comparison between RDS and other more traditional sampling methods such as venue-based, targeted or time/space sampling. The current study sampled injection drug users in three U.S. cities using RDS and targeted sampling (TS) methods and compared their effectiveness in terms of recruitment efficiency, logistics, and sample demographics. Both methods performed satisfactorily. The targeted method required more staff time per-recruited respondent and had a lower proportion of screened respondents who were eligible than RDS, while RDS respondents were offered higher incentives for participation.     

A flexible copula-based approach for the analysis of secondary phenotypes in ascertained samples

Data collected for a genome-wide association study of a primary phenotype are often used for additional genome-wide association analyses of secondary phenotypes. However, when the primary and secondary traits are dependent, naïve analyses of secondary phenotypes may induce spurious associations in non-randomly ascertained samples. Previously, retrospective likelihood-based methods have been proposed to correct for sampling biases arising in secondary trait association analyses. However, most methods have been introduced to handle studies featuring a case-control design based on a binary primary phenotype. As such, these methods are not directly applicable to more complicated study designs such as multiple-trait studies, where the sampling mechanism also depends on the secondary phenotype, or extreme-trait studies, where individuals with extreme primary phenotype values are selected. To accommodate these more complicated sampling mechanisms, only a few prospective likelihood approaches have been proposed. These approaches assume a normal distribution for the secondary phenotype (or the latent secondary phenotype) and a bivariate normal distribution for the primary-secondary phenotype dependence. In this paper, we propose a unified copula-based approach to appropriately detect genetic variant/secondary phenotype association in the presence of selected samples. Primary phenotype is either binary or continuous and the secondary phenotype is continuous although not necessary normal. We use both prospective and retrospective likelihoods to account for the sampling mechanism and use a copula model to allow for potentially different dependence structures between the primary and secondary phenotypes. We demonstrate the effectiveness of our approach through simulation studies and by analyzing data from the Avon Longitudinal Study of Parents and Children cohort.