Background

The objective of this study was to examine the relationship between cannabis and alcohol use and occurrence of motor vehicle collision (MVC) among patients in the emergency department (ED).

Methods

This was a cross-sectional study of visits to EDs in Denver, CO, Portland, OR, and Sacramento, CA by drivers who were involved in MVCs and presented with injuries (cases) and non-injured drivers (controls) who presented for medical care. We obtained blood samples and measured delta-9-THC and its metabolites. Alcohol levels were determined by breathalyzer or samples taken in the course of clinical care. Participants completed a research-assistant-administered interview consisting of questions about drug and alcohol use prior to their visit, context of use, and past-year drug and alcohol use. Multiple logistic regression was used to estimate the association between MVC and cannabis/alcohol use, adjusted for demographic characteristics. We then stratified participants based on levels of cannabis use and calculated the odds of MVC across these levels, first using self-report and then using blood levels for delta-9-THC in separate models. We conducted a case-crossover analysis, using 7-day look-back data to allow each participant to serve as their own control. Sensitivity analyses examined the influence of usual use patterns and driving in a closed (car, truck, van) versus open (motorcycle, motorbike, all-terrain vehicle) vehicle.

Results

Cannabis alone was not associated with higher odds of MVC, while acute alcohol use alone, and combined use of alcohol and cannabis were both independently associated with higher odds of MVC. Stratifying by level of self-reported or measured cannabis use, higher levels were not associated with higher odds for MVC, with or without co-use of alcohol; in fact, high self-reported acute cannabis use was associated with lower odds of MVC (odds ratio [OR] 0.18, 95% confidence interval [CI] 0.05–0.65). In the case-crossover analysis, alcohol use alone or in combination with cannabis was associated with higher odds of MVC, while cannabis use alone was again associated with decreased odds of MVC.

Conclusions

Alcohol use alone or in conjunction with cannabis was consistently associated with higer odds for MVC. However, the relationship between measured levels of cannabis and MVC was not as clear. Emphasis on actual driving behaviors and clinical signs of intoxication to determine driving under the influence has the strongest rationale.

中文翻译：

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接受紧急护理的患者与大麻和酒精使用相关的机动车碰撞风险

背景

本研究的目的是调查急诊科 (ED) 患者中大麻和酒精使用与机动车碰撞 (MVC) 发生率之间的关系。

方法

这是一项横断面研究，调查对象是参与 MVC 并出现受伤（病例）的司机和前来就医的未受伤司机（对照）前往科罗拉多州丹佛、俄勒冈州波特兰和加利福尼亚州萨克拉门托的急诊室。关心。我们获取了血液样本并测量了 delta-9-THC 及其代谢物。酒精浓度通过呼气分析仪或临床护理过程中采集的样本测定。参与者完成了由研究助理主持的访谈，其中包括访问前有关药物和酒精使用情况、使用背景以及过去一年药物和酒精使用情况的问题。使用多元逻辑回归来估计 MVC 与大麻/酒精使用之间的关联，并根据人口特征进行调整。然后，我们根据大麻使用水平对参与者进行分层，并计算这些水平上 MVC 的几率，首先使用自我报告，然后在单独的模型中使用 delta-9-THC 的血液水平。我们进行了病例交叉分析，使用 7 天回顾数据，让每个参与者作为自己的对照。敏感性分析检查了通常使用模式以及驾驶封闭式（汽车、卡车、货车）与开放式（摩托车、摩托车、全地形车）车辆的影响。

结果

单独使用大麻与较高的 MVC 几率无关，而单独急性饮酒以及酒精和大麻的联合使用均与较高的 MVC 几率独立相关。根据自我报告或测量的大麻使用水平进行分层，无论是否同时饮酒，较高的水平与较高的 MVC 几率无关；事实上，大量自我报告的急性大麻使用与较低的MVC 几率相关（优势比 [OR] 0.18，95% 置信区间 [CI] 0.05–0.65）。在病例交叉分析中，单独使用酒精或与大麻结合使用与 MVC 发生率较高相关，而单独使用大麻又与 MVC 发生率降低相关。

结论

单独使用酒精或与大麻一起使用始终与较高的 MVC 发生率相关。然而，测量到的大麻水平和 MVC 之间的关系并不那么清楚。强调实际驾驶行为和中毒临床症状来确定酒后驾驶具有最强的理论依据。