Pediatric Cannabis Poisoning Hospitalizations Doubled in Canada After Legalization of Edibles: Study

Cannabis ingestion has been identified as the cause of 1 in every 3 pediatric poisoning hospitalizations in Canadian provinces that permit the sale of edible varieties of the psychoactive drug. The findings come from a cross sectional study that included 3.4 million children aged ≤9 years living in Canada’s 4 most populous provinces.

Published in JAMA Health Forum, the study examined the rate of pediatric hospitalizations before cannabis legalization in Canada in October 2018 and also, importantly, during the period during which cannabis dried flower was legal but before regulated cannabis edibles were available. Some provinces permitted the sale of commercial edibles beginning in January 2020. The distinction allowed researchers to compare the impact on pediatric poisoning of the legalization of dried flower cannabis with the impact following the subsequent legalization of edibles.

Canada’s experience is not unique in North America. Evidence is rapidly accumulating in the US that suggests the legalization of recreational cannabis for use by adults is linked to rises in cannabis poisonings in children. For example, a study among poison control centers across the US between 2005 and 2011 found that calls for cannabis-related visits in children aged 0 to 9 years increased by 30.3% per year in states that had decriminalized cannabis vs 1.5% per year in states where cannabis remained illegal. Cannabis poisoning in young children, the authors stress, can be lethal. High-acuity presentations are common and include reduced consciousness, respiratory depression, and seizures.

Phased legalization

Canadian investigators, led by Yaron Finkelstein, MD, professor of Paediatrics and Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, took advantage of the country’s 2-phase process of cannabis product legalization to analyze the change in rate of all-cause hospitalizations for cannabis poisoning in children through 3 legalization policy periods over 8 years.

Nationally, the sale and use of recreational cannabis for adults aged ≥18 years was legalized in October 2018. Initially only the sale of dried cannabis flower was permitted and all provinces were legally required to allow those sales but could choose to allow or prohibit the sale of commercial edible products. Ontario, British Columbia, and Alberta (exposed provinces) permitted sale of cannabis edibles and THC-infused beverages in January 2020, while Quebec (control province) prohibited sale of edible products including candies, sweets and products that would be potentially attractive to children and young adults.

The investigators’ repeated, cross-sectional population-based study comprised all hospitalizations in children aged 0 to 9 years in the 4 provinces above between January 1, 2015, and September 30, 2021 and was divided into 3 policy periods:

• Prelegalization period (January 2015 – September 2018)
• Period 1, representing legalized dried flower, seeds, oil only in all provinces (October 2018 – December 2019)
• Period 2, representing legalized dried flower and edibles in Ontario, British Columbia, and Alberta and restriction in Quebec (control province) (January 2020 – September 2021).

FINDINGS

Researchers reported 581 pediatric hospitalizations for cannabis poisoning during the 7-year study period (2015 – 2021). The children’s mean age was 3.6 years and more than half (53.9%) were boys.

Investigators observed another 4406 hospitalizations for all-cause poisonings.

Among the all-cause poisoning hospitalizations, the rate per 1000 due to cannabis poisoning was 57.42 in the exposed provinces and 38.5 in the control province.

In period 1, following national legalization, the rate per 1000 more than doubled to to 149.71 in the 3 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 3 exposed provinces permitted edibles but Quebec continued to restrict the sale, 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).

“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,” wrote Finkelstein and colleagues. “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.”

“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 add that the overall increases in unintentional pediatric poisoning were not affected by reduction efforts by Canadian regulators including “a maximum of 10 mg THC per edible package (representing a 10-fold smaller amount than allowed in several US jurisdictions), plain and child-resistant packaging requirements, and consumer education campaigns.”

“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 concluded.

Reference: Myran DT, Tanuseputro P, Auger N, et al. Pediatric hospitalizations for unintentional cannabis poisonings and all-cause poisonings with edible cannabis product legalization and sales in Canada. JAMA Health Forum. 2023;4:e225041. doi:10.1001/jamahealthforum.2022.5041