Pediatric Cannabis Poisoning Hospitalizations Spiked in Canada After Edible Legalization

Daniel T. Myran, MD, MPH

The legalization of cannabis in Canada, and corresponding availability of edible cannabis products, was associated with a major increase in the rate of poisoning-related hospitalizations among children.

There has been a clear correlation between the availability of legal cannabis and edible products and a rising prevalence of unintentional pediatric cannabis-related poisonings since 2018, according to new data from investigators at Ottawa Hospital Research Institute. Findings from their cross-sectional analysis of pediatric hospitalizations show the correlation is significant enough that cannabis is now a nationally leading cause of pediatric poisoning hospitalizations—an issue that investigators warned may burden countries with increasing cannabis legalization and marketing such as the United States.

Led by Daniel T. Myran, MD, MPH, investigators sought to analyze the change in rate of all-cause poison hospitalizations due to cannabis in children aged 0-9 years old across Canada’s 4 most populous provinces throughout a series of 3 legalization policy periods from the last 8 years.

Citing ongoing discussions among the US Senate to federally legalize recreational cannabis, the team noted a growing field of evidence that cannabis legalization is positively correlated with pediatric cannabis poisonings; such cases generally present with concerning, high-acuity conditions including decreased consciousness, respiratory depression and seizures.

Canada legalized recreational cannabis for adults ≥18 years old in October 2018, using a 2-phase strategy that allowed provinces to permit or prohibit sale of expanded commercial edible products alongside mandatory dried cannabis flower; Ontario, British Columbia and Alberta permitted sale of cannabis edibles and THC-infused beverages in January 2020, while Quebec prohibited sale of edible products that included candies, sweets and products that would be potentially attractive to children and young adults.

As such, investigators analyzed these 4 provinces—the most populous in Canada—across 3 states of legalization: pre-legalization (January 2015 – September 2018); period 1, representing legalized dried flower (October 2018 – December 2019); and period 2, representing legalized dried flower and edibles in the 3 provinces (exposed provinces) and restriction in Quebec (control province) (January 2020 – September 2021).

Myran and colleagues observed 581 pediatric hospitalizations for cannabis poisoning from 2015 – 2021; a majority of patients were boys (53.9%), and mean age was 3.6 years old. Investigators additionally observed another 4406 hospitalizations for all-cause poisonings.

Among the all-cause poisoning hospitalizations, the rate per 1000 hospitalizations due to cannabis poisoning was 57.42 in exposed provinces and 38.5 in the control province. In period 1, following legalization, the rate per 1000 poisoning hospitalizations increased to 149.71 in exposed provinces (incidence rate ratio [IRR], 2.55; 95% CI, 1.88 – 3.46) and to 117.52 in the control province (IRR, 3.05; 95% CI, 1.82 – 5.11).

In period 2, when the exposed provinces permitted edibles, the rate per 1000 poisonings due to cannabis again more than doubled to 318.04 among exposed provinces (IRR, 2.16; 95% CI, 1.68 – 2.80), but remained at a similar rate of 137.93 in Quebec (IRR, 1.18; 95% CI, 0.71 – 1.97).

With approximately 1 in every 3 pediatric poisoning hospitalizations involving cannabis in provinces with legalized dry leaf and edible cannabis products, Myran and colleagues stressed these findings may provide state- and country-level legislators insight into best policies and strategies in place to mitigate risk in places where cannabis is legalized.

“Our findings of disparate proportions of pediatric poisonings in Quebec and Ontario, despite the comparable overall dollar value of legal cannabis sales during the study, suggest that product type rather than sales volume is a key factor associated with pediatric poisonings,” they wrote. “The large increase in harms associated with the sale of commercial cannabis edibles and concentrates in exposed jurisdictions suggests that restricting or prohibiting the sale of these products could be a highly effective regulatory act to reduce the frequency and severity of unintentional pediatric poisonings.”

They additionally recommended consideration of child-resistant or unit-dose packaging to avoid overexposure risk, as well as increased public health messaging around the risk of pediatric cannabis consumption. Indeed, a key facet to reducing the impact of cannabis legalization on pediatric hospitalizations is in the very marketing and promotion of the product.

“Our findings suggest that placing restrictions on the sale of visually attractive and palatable commercial cannabis edibles is a key strategy and policy consideration for preventing unintentional pediatric cannabis poisonings for the US and other countries considering legalization of recreational cannabis,” they wrote.

The study, “Pediatric Hospitalizations for Unintentional Cannabis Poisonings and All-Cause Poisonings Associated With Edible Cannabis Product Legalization and Sales in Canada,” was published online in JAMA Health Forum.