"The Colorado Department of Public Health and Environment (CDPHE) analyzed data from the
Colorado Hospital Administration (CHA) with these findings:

"Hospitalization rates (per 100,000 hospitalizations) with possible marijuana exposures, diagnoses, or billing codes increased from 803 per 100,000 before commercialization (2001‐2009) to 2,696 per 100,000 after commercialization (January 2014‐September 2015). The period from October 2015‐December 2015 indicated another increase, but due to changes in coding systems, variable structures, and policies at CHA, the numbers for 2016 are considered preliminary by CDPHE.

"The period of retail commercialization showed an increase in emergency department visits, from 739 per 100,000 ED visits (2010–2013) to 913 per 100,000 ED visits (January 2014–September 2015). There was no definitive trend during the period October 2015‐December 2015 and, due to changes in coding systems, variable structures, and policies at CHA, these figures for 2016 are considered preliminary by CDPHE.

"The number of calls to poison control mentioning human marijuana exposure increased over the past 10 years. There were 45 calls in 2006 and 222 in 2017. Between 2014 and 2017, the frequency of calls reporting human marijuana exposure stabilized."

Source

Impacts of Marijuana Legalization in Colorado: A Report Pursuant to Senate Bill 13-283. Colorado Department of Public Safety, Division of Criminal Justice, Office of Research and Statistics. October 2018.