Marijuana Exposures Reported to the Rocky Mountain Poison and Drug Center

BACKGROUND:  The Rocky Mountain Poison and Drug Center (RMPDC)  provides medical information to health care providers and the public aimed at reducing toxicity, injury and disease related to exposures of all kinds. The legal status of marijuana use has changed over time in Colorado. Since 2001, when medical marijuana use was legalized, RMPDC has compiled data on Colorado calls reporting marijuana exposure.  We sought to evaluate whether the change in legal status of marijuana use over time resulted in a change in the volume of calls received by RMPDC for reported marijuana exposures. 

METHODS: The RMPDC data was queried to assess counts of calls received regarding marijuana exposures. Counts of calls related to possible marijuana exposures were quantified over time by years for calls with marijuana exposures only and calls with marijuana exposures and other drug exposures. Counts of calls with possible marijuana exposures were stratified into 4 age categories: 0-9 years, 10-17 years, 18-24 years, 25 years or older, and unknown age. To determine significant differences in numbers of calls related to marijuana across years, a Wald Chi-square test was performed using univariate Poisson regression. A Bonferroni correction was used to adjust for multiple comparisons. There were 13 comparisons made making the p value required for significance less than or equal to 0.004.

RESULTS: From 2001 to 2009, calls to the poison center related to marijuana remained constant. However, in 2010 calls related to marijuana significantly increased by more than double from  44 to 95 (Χ²(1, N=1,226)=17.82, p<0.0001). From 2010 to 2013 counts of calls related to marijuana did not significantly increase. Then in 2014 calls related to marijuana significantly increased by 74.0% from 127 to 221(Χ²(1, N=1,226)=24.75, p<0.0001). These increases appear to be drive by both calls with marijuana exposure only and marijuana exposure and other drug exposure . All age categories show increasing trends in counts of call related to marijuana exposures with the highest burden in children aged 0-9 years and adults 25 years and older.

CONCLUSIONS:   These preliminary findings suggest counts of calls for marijuana exposures and possible adverse health outcomes have increased overall and across age categories over marijuana legalization eras since year 2000. Since not all individials that experience marijuana exposure related symptoms requiring treatment call the RMPDC , this number of calls is likely an underestimate of the population that needs urgent or emergency medical services for symptoms related to marijuana exposure.