Article Text

Download PDFPDF
Alcohol and cannabis use in traffic-related injuries in Mexico City
  1. Guilherme Borges,
  2. Ricardo Orozco
  1. Center of Global Mental Health, National Institute for Psychiatry Ramon de la Fuente Muniz, Ciudad de Mexico, Mexico
  1. Correspondence to Dr Guilherme Borges, National Institute for Psychiatry Ramon de la Fuente Muniz, Ciudad de Mexico, Mexico; guilhermelgborges{at}


Bacterkground There is debate on whether cannabis affects road traffic injuries (RTIs) separately from the effects of alcohol. Our goals are to report the possible increase in risk of an RTI among alcohol and cannabis users by type of exposure (biological, self-reported and combined) and the possible interaction of alcohol and cannabis in patients with an RTI in an emergency department in Mexico City.

Methods A case–crossover study with 433 cases of RTI (as a pedestrian, driver or passenger) during the period January–April 2022. A breath sample, an oral sample for cannabis detection and self-reported alcohol and cannabis use 6 hours prior to the RTI and in two control periods were used. We report ORs and 95% CIs from conditional logistic regressions for the case–crossover estimates.

Results Alcohol alone increased the risk of an RTI (OR=6.02, 95% CI 3.29 to 10.99) for most RTIs, regardless of whether we used information from self-reports or a breath sample in the hazard period. Conversely, cannabis only increased the RTI when we added information in the hazard period from self-reports or oral samples. Nevertheless, this increase in risk disappeared (OR=2.06, 95% CI 0.90 to 4.70) among those who only used cannabis. We also found no evidence of interaction between alcohol and cannabis in the risk of an RTI.

Conclusions Alcohol is the most commonly used substance in Mexico and a high-risk factor for RTI in Mexico City. Although cannabis alone was not associated with an RTI, continuous monitoring of its effects is required.

  • Epidemiology
  • Alcohol
  • Drugs

Data availability statement

No data are available. No data is available for public use.

This article is made freely available for personal use in accordance with BMJ’s website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Data availability statement

No data are available. No data is available for public use.

View Full Text


  • Contributors The initial draft of this paper was prepared by GB in cooperation with RO. GB confirms that he had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. GB and RO were responsible for obtaining funding. GB and RO participated in the study concept and design. GB and RO participated in the analysis and interpretation of data. All authors reviewed initial drafts for substantive inputs and approved the final version of the article. GB accepts full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish.

  • Funding This study was supported by the Sectoral Research Fund for Education SEP-CONACYT Basic Science under Grant A1-S-8190 'Uso de sustancias psico-activas y accidentes de tránsito'. Principal investigator: GB.

  • Disclaimer All authors acknowledge that there was no financial interest in or benefit from the direct application of this research.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.