Drug tourism to Mexico: Impact of Mexicos new drug law on HIV-HCV-TB in US IDUs

描述(由申请人提供)：这项拟议的为期5年的流行病学研究的目标是评估墨西哥新毒品法对美国注射吸毒者(IDU)行为和疾病发病率的影响。2009年8月，墨西哥颁布了一项有争议的法律，将拥有个人数量的毒品(包括海洛因、可卡因、甲基苯丙胺和大麻)合法化。美国加利福尼亚州圣地亚哥和墨西哥不列颠哥伦比亚省蒂华纳这两个姐妹城市共享世界上最繁忙的陆地边境口岸，居住着近400万居民。通过与加州大学圣地亚哥分校和提华纳的合作伙伴的研究合作，我们发现：i)提华纳的毒品使用和艾滋病毒流行率不断上升；ii)提华纳与圣地亚哥的注射吸毒者中丙型肝炎病毒(丙型肝炎病毒)和结核分枝杆菌(Mtb)的感染率大幅上升；以及iii)圣地亚哥21%的注射吸毒者报告在墨西哥注射。圣迪根注射吸毒者前往墨西哥的“毒品旅游”可能是墨西哥放宽毒品法律的意外后果，可能会增加他们感染丙型肝炎病毒、结核分枝杆菌和艾滋病毒的风险。这项流行病学研究旨在：1)确定在墨西哥注射和不注射的圣地亚哥注射吸毒者之间的社会人口学、行为和健康状况的差异；2)描述圣地亚哥注射吸毒者与墨西哥毒品政策相关的知识、态度和经历的变化，并评估它们对在墨西哥注射的决定的影响；以及3)确定在墨西哥注射的注射吸毒者是否面临感染丙型肝炎病毒和结核分枝杆菌的风险增加，并确定感染的风险因素。为了达到这些目标，我们将使用包括定量和定性数据收集的混合方法设计。量化方法包括通过受访者驱动的抽样在圣地亚哥招募750名注射吸毒者，进行每半年一次的行为评估，并在24个月的随访中进行艾滋病毒、丙型肝炎病毒和结核分枝杆菌感染的血清学测试。艾滋病毒和丙型肝炎病毒抗体检测将使用标准做法对血清进行；结核分枝杆菌感染将通过Quantiferon TB-Gold检测。定性方法包括在每次评估访问(总计=100)后选择20名参与者进行深入访谈，这些访谈将用于：1)探索在对量化数据的初步分析中出现的新发现；2)确定除量化评估之外的新的调查领域；3)通过向定性访谈的研究参与者展示量化结果以供解释，以评估量化结果的有效性。使用定性和定量数据为方法提供信息并解释每种方法的结果的迭代过程，有助于全面理解描述墨西哥新法律将如何影响圣地亚哥注射吸毒者的行为和健康结果的概念模型。这项研究符合NIDA的优先事项，支持对包括丙型肝炎病毒和结核病在内的艾滋病毒/艾滋病共病的流行病学研究，以及在脆弱人群中预防艾滋病毒。这项研究利用一个罕见的自然实验来评估反对毒品政策对相互关联的、边缘社区的影响，并将为未来的政策提供重要的见解。 公共卫生相关性：注射吸毒者受艾滋病毒、丙型肝炎和结核病的影响不成比例，最近在墨西哥提华纳--加利福尼亚州圣地亚哥的姊妹城市--承认这些疾病汇聚在一起，这表明如果没有有效的干预措施，疾病的进展和传播率将会增加。2010年8月，墨西哥颁布了新的立法，将持有个人数量的麻醉药品(如甲基苯丙胺、海洛因、可卡因和大麻)合法化，担心这将鼓励更多的美国注射吸毒者前往墨西哥购买和使用毒品。在NIDA资助的一项研究将评估该法律对提华纳注射吸毒者的影响的同时，我们将进行一项纵向队列研究，以检查该法律对圣地亚哥注射吸毒者的行为和疾病风险的影响，这些注射吸毒者可以很容易地越过边境往返墨西哥。

DESCRIPTION (provided by applicant): The goal of the proposed 5-year epidemiologic study is to assess the impact of Mexico's new drug laws on behaviors and disease incidence among injection drug users (IDUs) in the U.S. In August, 2009, Mexico enacted a controversial law decriminalizing possession of personal-sized quantities of drugs including heroin, cocaine, methamphetamine and cannabis. The sister-cities of San Diego, CA, USA and Tijuana, BC, Mexico share the world's busiest land border crossing and are home to nearly 4 million residents. Through research collaborations with the University of California, San Diego and partners in Tijuana, we found: i) increasing drug use and HIV prevalence in Tijuana; ii) dramatically higher prevalence of hepatitis C virus (HCV) and M. tuberculosis (Mtb) infections among IDUs in Tijuana versus San Diego; and, iii) injecting in Mexico reported by 21% of IDUs in San Diego. "Drug tourism" to Mexico among San Diegan IDUs may be an unintended consequence of Mexico's relaxed drug laws and could increase their risk for HCV, Mtb and HIV infections. This epidemiologic study aims to: 1) identify sociodemographic, behavioral, and health status differences between IDUs in San Diego who do and do not inject in Mexico; 2) describe changes in San Diegan IDUs' knowledge, attitudes, and experiences related to Mexican drug policies and assess their influences on decisions about injecting in Mexico; and 3) determine whether San Diegan IDUs who inject in Mexico are at increased risk for incident HCV and Mtb infection and identify risk factors for infection. To achieve these aims, we will use a mixed-methods design involving quantitative and qualitative data collection. Quantitative methods include recruiting a cohort of 750 IDUs in San Diego via respondent driven sampling for semi-annual behavioral assessments and serologic testing for HIV, HCV, and Mtb infections over 24 months of follow-up. HIV and HCV antibody testing will be performed on serum using standard practices; Mtb infection will be detected by QuantiFERON TB-Gold assay. Qualitative methods involve selecting 20 participants after each assessment visit (total=100) for in-depth interviews that will be used to: i) explore novel findings that emerge in preliminary analysis of the quantitative data; ii) identify new areas of inquiry for addition to the quantitative assessments; and iii) assess the validity of quantitative findings by presenting them for interpretation to study participants in qualitative interviews. The iterative process of using qualitative and quantitative data to inform methods and interpret findings of each approach facilitates a comprehensive understanding of the conceptual model describing how Mexico's new law will impact the behaviors and health outcomes of IDUs in San Diego. This study meets NIDA priorities supporting epidemiologic research on HIV/AIDS co-morbidities including HCV and tuberculosis, and the prevention of HIV among vulnerable populations. This study exploits a rare natural experiment to evaluate the impact of opposing drug policies on interconnected, bordering communities, and will provide important insights for future policies. PUBLIC HEALTH RELEVANCE: Injection drug users (IDUs) are disproportionately affected by HIV, hepatitis C, and tuberculosis, and, the recently recognized convergence of these diseases in Tijuana, Mexico-sister city to San Diego, CA- suggests that progression of disease and rates of transmission will increase without effective interventions. In August, 2010 Mexico enacted new legislation decriminalizing possession of personal-size quantities of narcotic drugs (e.g., methamphetamine, heroin, cocaine, and cannabis), which it is feared will encourage more U.S. IDUs to visit Mexico to buy and use drugs. In parallel with a NIDA-funded study that will assess the law's impact on IDUs in Tijuana, we will conduct a longitudinal cohort study to examine the law's impact on the behaviors and disease risks among IDUs in San Diego who can readily cross the border to and from Mexico.