Single-substance cannabis exposure calls to poison control for children and teens increased 140% after Massachusetts legalized medical marijuana, with edible product exposures rising across most age groups.
Parents, pediatricians, and policymakers designing cannabis safety regulations.
140% increase in pediatric cannabis exposure calls
What the researchers found
Single-substance cannabis calls increased from 0.4 to 1.1 per 100,000 population after medical marijuana legalization (IRR 2.4, 95% CI 1.5-3.9), a 140% increase. Teens aged 15-19 accounted for 81.7% of all calls. Edible product exposures increased after legalization across most age groups. Over the 8-year period, 218 total cannabis exposure calls were received (98 single-substance, 120 polysubstance).
Why it matters
Despite childproof packaging and warning labels, pediatric exposures still increased, suggesting these measures alone are insufficient to protect children in legal cannabis markets.
The numbers in context
218 total calls over 8 years (2009-2016). 140% increase in single-substance calls (IRR 2.4). 60.6% male. 81.7% aged 15-19. Single-substance calls: 29 before vs 69 after legalization.
How the study worked
Cross-sectional comparison of pediatric cannabis exposure cases reported to the Regional Center for Poison Control and Prevention, comparing 4 years before and after medical marijuana legalization in Massachusetts (2009-2016).
What this study cannot tell us
Poison control data likely undercount actual exposures. Cannot determine causation. Temporal association with legalization does not prove legalization caused the increase. No data on severity or outcomes.
How to read the evidence
Registry-based study with clear before/after comparison, but poison control data have known underreporting.
When this study was published
2019 study using 2009-2016 data.
The bigger picture
This adds to evidence from Colorado and Washington showing pediatric cannabis exposures increase after legalization, extending the pattern to the East Coast.
Questions still open
- Are current packaging and labeling requirements effective for preventing very young children from accessing edibles? How do exposure rates change after recreational legalization?
Common questions
Did pediatric cannabis poisoning increase after legalization?
Which age group had the most cannabis exposures?
Read the original research
Incidence of Pediatric Cannabis Exposure Among Children and Teenagers Aged 0 to 19 Years Before and After Medical Marijuana Legalization in Massachusetts.
JAMA network open, 2(8), e199456
Citation
Whitehill, Jennifer M; Harrington, Calla; Lang, Cheryl J; Chary, Michael; Bhutta, Waqaas A; Burns, Michele M. (2019). Incidence of Pediatric Cannabis Exposure Among Children and Teenagers Aged 0 to 19 Years Before and After Medical Marijuana Legalization in Massachusetts.. JAMA network open, 2(8), e199456. https://doi.org/10.1001/jamanetworkopen.2019.9456