加拿大不列颠哥伦比亚大学Jeffrey R. Brubacher团队研究了大麻合法化后四氢大麻酚在受伤司机中的检出趋势。该研究于2022年1月12日发表在《新英格兰医学杂志》上。

加拿大大麻合法化（2018年10月）对四氢大麻酚（THC）检测呈阳性的受伤司机的影响尚不清楚。

利用2013年1月到2020年3月的数据，课题组研究了在不列颠哥伦比亚省的四个创伤中心接受机动车碰撞治疗的司机，包括中度受伤的司机（临床评估的一部分需要进行血液检测），他们在临床检测完成后仍有多余的血液。

这些血液在省毒理学中心进行了分析。主要结局是THC水平大于0，THC水平至少为2 ng/毫升（加拿大法定限度），THC水平至少为5 ng/毫升。次要结局是THC水平至少为2.5 ng/毫升，血液酒精水平至少为0.05%；THC水平大于0的，血液酒精含量至少为0.08%。

研究组计算了合法化前后所有结局的流行率。在对相关协变量进行校正后，研究组使用对数二项回归对药物流行率和合法化之间的关系进行建模，从而获得校正后的流行率。

在研究期间，符合纳入标准的司机有4339名，其中合法化前3550名，合法化后789名。在大麻合法化之前，9.2%的司机检测到THC水平大于0，3.8%的司机至少为2 ng/毫升，1.1%的司机至少为5 ng/毫升。合法化后分别为17.9%、8.6%和3.5%。

合法化后，司机检测到THC水平大于0、至少为2 ng/毫升、至少为5 ng/毫升的流行率有所增加，校正后的风险比分别为1.33、2.29和2.05。在50岁及以上的驾驶员（校正后风险比为5.18）和男性驾驶员（2.44）中THC水平至少为2 ng/毫升的比率增幅最大。酒精检测呈阳性的司机流行率没有显著变化。

研究结果表明，大麻合法化后，不列颠哥伦比亚省创伤中心中度受伤司机中THC水平至少为2 ng/毫升的流行率增加了一倍以上。年龄较大的司机和男性司机的增幅最大。

附：英文原文

Title: Cannabis Legalization and Detection of Tetrahydrocannabinol in Injured Drivers

Author: Jeffrey R. Brubacher, M.D.,, Herbert Chan, Ph.D.,, Shannon Erdelyi, M.Sc.,, John A. Staples, M.D.,, Mark Asbridge, Ph.D.,, and Robert E. Mann, Ph.D.

Issue&Volume: 2022-01-12

Abstract:

Background

The effect of cannabis legalization in Canada (in October 2018) on the prevalence of injured drivers testing positive for tetrahydrocannabinol (THC) is unclear.

Methods

We studied drivers treated after a motor vehicle collision in four British Columbia trauma centers, with data from January 2013 through March 2020. We included moderately injured drivers (those whose condition warranted blood tests as part of clinical assessment) for whom excess blood remained after clinical testing was complete. Blood was analyzed at the provincial toxicology center. The primary outcomes were a THC level greater than 0, a THC level of at least 2 ng per milliliter (Canadian legal limit), and a THC level of at least 5 ng per milliliter. The secondary outcomes were a THC level of at least 2.5 ng per milliliter plus a blood alcohol level of at least 0.05%; a blood alcohol level greater than 0; and a blood alcohol level of at least 0.08%. We calculated the prevalence of all outcomes before and after legalization. We obtained adjusted prevalence ratios using log-binomial regression to model the association between substance prevalence and legalization after adjustment for relevant covariates.

Results

During the study period, 4339 drivers (3550 before legalization and 789 after legalization) met the inclusion criteria. Before legalization, a THC level greater than 0 was detected in 9.2% of drivers, a THC level of at least 2 ng per milliliter in 3.8%, and a THC level of at least 5 ng per milliliter in 1.1%. After legalization, the values were 17.9%, 8.6%, and 3.5%, respectively. After legalization, there was an increased prevalence of drivers with a THC level greater than 0 (adjusted prevalence ratio, 1.33; 95% confidence interval [CI], 1.05 to 1.68), a THC level of at least 2 ng per milliliter (adjusted prevalence ratio, 2.29; 95% CI, 1.52 to 3.45), and a THC level of at least 5 ng per milliliter (adjusted prevalence ratio, 2.05; 95% CI, 1.00 to 4.18). The largest increases in a THC level of at least 2 ng per milliliter were among drivers 50 years of age or older (adjusted prevalence ratio, 5.18; 95% CI, 2.49 to 10.78) and among male drivers (adjusted prevalence ratio, 2.44; 95% CI, 1.60 to 3.74). There were no significant changes in the prevalence of drivers testing positive for alcohol.

Conclusions

After cannabis legalization, the prevalence of moderately injured drivers with a THC level of at least 2 ng per milliliter in participating British Columbia trauma centers more than doubled. The increase was largest among older drivers and male drivers.

DOI: NJ202201133860210

Source: https://www.nejm.org/doi/full/10.1056/NEJMsa2109371