Lausanne, Switzerland: The use of cannabis is not a contributing causal factor in injuries requiring hospitalization, and may even protect users against the likelihood of sustaining such injuries, according to the results of case-control study published online in the journal BMC Public Health.

Investigators at the Luasanne University Hospital in Switzerland assessed the association between the use of cannabis and/or alcohol and the risk of injury among 486 patients aged 16 and older.

Investigators reported: “Alcohol use in the six hours prior to injury was associated with [an elevated] relative risk compared with no alcohol use. Cannabis use was inversely related to risk of injury.”

Researchers also analyzed subjects’ drug use for the time period exactly one week prior to the patients’ hospitalization. They reported, “More patients reported alcohol use in the six-hour period prior to injury (case period) than in the corresponding six-hour period the previous week (control period). … For cannabis, fewer people reported use prior to injury (case period) than in the control period.”

Despite the study’s relatively small sample size, investigators concluded: “The results for cannabis use were quite surprising. … The present study in fact indicated a ‘protective effect’ of cannabis use in a dose-response relationship.”

Commenting on the study’s results, authors speculated that “cannabis is consumed in relatively safer, low risk environments” (e.g., at home) compared to alcohol, which is often consumed at bars or prior to going out in public.

A prior case-control study conducted by the University of Missouri also reported an inverse relationship between marijuana use and injury risk, finding, “Self-reported marijuana use in the previous seven days was associated … with a substantially decreased risk of injury.”

For more information, please contact Paul Armentano, NORML Deputy Director, at: paul@norml.org. Full text of the study, “Alcohol and cannabis use as risk factors for injury – a case-crossover analysis in a Swiss hospital emergency department,” is available online from BMC Public Health at: www.biomedcentral.com/1471-2458/9/40.