Cannabis use and health outcomes among opioid-using people who inject drugs in the context of cannabis legalization

项目摘要 我们提出了一项纵向的前瞻性队列研究，以确定大麻使用频率的变化 与阿片类药物使用频率和阿片类药物使用相关健康结果的变化有关， 使用（海洛因和处方阿片类药物）的人谁注射毒品（PWID）在两个州与法律的成年人 大麻的销售和使用。州一级成人大麻销售和使用合法化可能会导致更大的 弱势群体中大麻的使用和与大麻相关的健康问题。然而， 大麻的销售和使用可能会对PWID产生意想不到的后果。初步研究表明 在药用大麻患者和社区招募的PWID中用大麻替代阿片类药物。 生态研究发现，医用大麻合法化与阿片类药物的低发病率有关， 相关的过量和住院治疗，结果可能是观察到的法律的成人使用大麻。基于 根据这些发现，我们推测大麻的使用可能会减少阿片类药物的使用，从而降低阿片类药物的风险。 相关药物危害，如非致命性过量事件。因此，我们提出以下目标： 目的1：确定大麻使用的变化是否与阿片类药物使用频率的变化相关 使用阿片类药物的PWID中，同时调整混杂因素。假设1（H1）：大麻的变化率 随着时间的推移，使用情况将与同期类阿片使用情况的变化率呈负相关。 目的2：确定使用阿片类药物的PWID中大麻使用的变化是否与 在非致死性用药过量事件中，同时调整混杂因素。H2：大麻使用的变化率将是 与非致死性用药过量事件数量的变化率呈负相关。 为了实现这些目标，我们建议在基线、6个月和12个月时进行招募、面试和随访， 在科罗拉多州丹佛市（N=500）和加利福尼亚州洛杉矶的1，000例阿片类药物使用PWID的前瞻性纵向队列 （N=500）。使用阿片类药物的PWID将使用有针对性的抽样方法招募。多个观察期 大样本量将允许使用尖端统计技术，如潜在增长模型 和有限混合模型来严格检验我们的假设。我们的两个网站可以让我们观察药物使用情况 不同种族/民族的PWID之间的模式和健康结果。非致命性用药过量的发生率 近年来有所增加。在我们的2016/17年洛杉矶PWID样本（n=472）中，21%报告了非致命性 在过去6个月内过量，这意味着拟定样本应具有足够的非致死性过量 事件，以允许统计分析随时间的变化，如这里所建议的。研究结果将促进药物使用 流行病学，并可能为减少毒品相关危害的新预防计划提供信息。我们的研究 团队是多学科的（经济学[Pacula]，流行病学[Corsi，Kral]，心理学[Booth & Huh]， 社会学[Bluthenthal]），并准备好进行这项重要的，创新的，严格的4年研究 项目

Project Summary We propose a longitudinal, prospective cohort study to determine if changes in cannabis use frequency are associated with changes in frequency of opioid use and drug-use related health outcomes among opioid- using (both heroin and prescription opiates) people who inject drugs (PWID) in two states with legal adult cannabis sales and use. State-level legalization of adult cannabis sales and use is likely to lead to greater cannabis use and cannabis-related health problems among vulnerable populations. However, increases in cannabis sales and use might have unanticipated consequences for PWID. Preliminary studies suggest substitution of cannabis for opioids among medicinal cannabis patients and community recruited PWID. Ecological studies have found that medical marijuana legalization is associated with lower rates of opioid- related overdose and hospitalization, outcomes that might be observable for legal adult use cannabis. Based on these findings, we theorize that cannabis use may reduce opioid use and thereby lower the risk for opioid- related drug harms such as nonfatal overdose events. Therefore, we propose the following aims: AIM 1: To determine whether changes in cannabis use are associated with changes in frequency of opioid use among opioid-using PWID while adjusting for confounders. Hypothesis 1 (H1): The rate of change in cannabis use over time will be inversely associated with the rate of change in opioid use during the same period. AIM 2: To determine whether changes in cannabis use among opioid-using PWID is associated with changes in non-fatal overdose events while adjusting for confounders. H2: The rate of change in cannabis use will be inversely associated with the rate of change in the number of non-fatal overdose events. To achieve these aims, we propose to recruit, interview, and follow at baseline, 6 and 12 months a prospective, longitudinal cohort of 1,000 opioid-using PWID in Denver, CO (N=500) and Los Angeles, CA (N=500). Opioid-using PWID will be recruited using targeted sampling methods. Multiple observation periods and large sample size will permit the use of cutting edge statistical techniques such as latent growth modelling and finite mixture modelling to rigorously test our hypotheses. Our two sites allow us to observe drug use patterns and health outcomes among racially/ethnically diverse PWID. The prevalence of non-fatal overdoses has increased in recent years. In our 2016/17 sample of Los Angeles PWID (n=472), 21% reported a non-fatal overdose in the last 6 months, meaning the proposed sample should have sufficient non-fatal overdoses events to permit statistical analyses of changes over time as proposed here. Findings will advance drug use epidemiology and may inform new prevention programs for the reduction of drug-related harms. Our study team is multidisciplinary (economics [Pacula], epidemiology [Corsi, Kral], psychology [Booth & Huh], and sociology [Bluthenthal]) and well-prepared to conduct this significant, innovative, and rigorous 4-year research project.