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    Original Investigation
    Emergency Medicine
    August 16, 2019

    Incidence of Pediatric Cannabis Exposure Among Children and Teenagers Aged 0 to 19 Years Before and After Medical Marijuana Legalization in Massachusetts

    Author Affiliations
    • 1Department of Health Promotion and Policy, University of Massachusetts Amherst, Amherst
    • 2Massachusetts Department of Public Health, Division of Violence and Injury Prevention, Boston
    • 3Regional Center for Poison Control and Prevention, Boston, Massachusetts
    • 4Harvard Medical School, Boston, Massachusetts
    • 5Division of Emergency Medicine, Boston Children’s Hospital, Boston, Massachusetts
    JAMA Netw Open. 2019;2(8):e199456. doi:10.1001/jamanetworkopen.2019.9456
    Key Points español 中文 (chinese)

    Question  Does the number of pediatric cannabis (marijuana) exposure cases before medical marijuana legalization in Massachusetts differ from the number afterward?

    Findings  In this repeated cross-sectional study, there were 218 calls related to cannabis exposure received by the Regional Center for Poison Control and Prevention in Massachusetts, constituting 0.15% of all calls concerning children and teenagers aged 0 to 19 years. The number of calls regarding single-substance cannabis exposure, especially edible product exposure, in this age group showed a statistically significant increase; the number of such calls for all cannabis product types more than doubled from 29 calls 4 years before MML to 69 calls 4 year afterwards.

    Meaning  This study suggests that states liberalizing marijuana policies should consider strengthening regulations to prevent unintentional exposure among young children and enhancing efforts to prevent use by teenagers, with particular attention to edible cannabis products and concentrated extracts.


    Importance  Pediatric health care contacts due to cannabis exposure increased in Colorado and Washington State after cannabis (marijuana) policies became more liberal, but evidence from other US states is limited.

    Objective  To document the incidence of pediatric cannabis exposure cases reported to the Regional Center for Poison Control and Prevention (RPC) before and after medical marijuana legalization (MML) in Massachusetts.

    Design, Setting, and Participants  Cross-sectional comparison of pediatric cannabis exposure cases 4 years before and after MML in Massachusetts. The exposure cases included those of 218 children and teenagers aged between 0 and 19 years, as reported to the RPC from 2009 to 2016. Census data were used to determine the incidence. Data analysis was performed from November 12, 2018, to July 20, 2019.

    Exposure  Cannabis products.

    Main Outcomes and Measures  Incidence of RPC-reported cannabis exposure cases, both single substance and polysubstance, for the age group of 0 to 19 years, and cannabis product type, coingestants, and clinical effects.

    Results  During the 8-year study period (2009-2016), the RPC received 218 calls involving cannabis exposure (98 single substance, 120 polysubstance) in children and teenagers aged 0 to 19 years, representing 0.15% of all RPC calls in that age group for that period. Of the total exposure cases, males accounted for 132 (60.6%) and females 86 (39.4%). The incidence of single-substance cannabis calls increased from 0.4 per 100 000 population before MML to 1.1 per 100 000 population after (incidence rate ratio, 2.4; 95% CI, 1.5-3.9), a 140% increase. The age group of 15 to 19 years had the highest frequency of RPC-reported cannabis exposures (178 calls [81.7%]). The proportion of all RPC calls due to single-substance cannabis exposure increased overall for all age groups from 29 before MML to 69 afterward. Exposure to edible products increased after MML for most age groups.

    Conclusions and Relevance  Pediatric cannabis exposure cases increased in Massachusetts after medical marijuana was legalized in 2012, despite using childproof packaging and warning labels. This study provides additional evidence suggesting that MML may be associated with an increase in cannabis exposure cases among very young children, and extends prior work showing that teenagers are also experiencing increased cannabis-related health system contacts via the RPC. Additional efforts are needed to keep higher-potency edible products and concentrated extracts from children and teenagers, especially considering the MML and retail cannabis sales in an increasing number of US states.