Association between cannabis laws and opioid prescriptions among privately insured adults in the US

We examine the association between opioid prescription patterns in privately insured adults and changes in state cannabis laws among five age groups (18-25, 26-35 36-45, 46-55 and 56-64 years). Using the 2016 Clinformatics Data Mart, a nationwide commercial health insurance database, we performed a cross-sectional analysis of two types of opioid prescribing (>30-day and >90-day prescriptions) among all adults aged 18-64 based on the stringency of cannabis laws. We found a significant interaction between age and cannabis law on opioid prescriptions. Age-stratified multilevel multivariable analyses showed lower opioid prescription rates in the four younger age groups only in states with medical cannabis laws, when considering both >30 day and >90 day opioid use [>30 day adjusted odds ratio (aOR) = 0.56, in 18-25, aOR = 0.67 in 26-35, aOR = 0.67 in 36-45, and aOR = 0.76 in 46-54 years; >90 day aOR = 0.56, in 18-25, aOR = 0.68 in 26-35, aOR = 0.69 in 36-45, and aOR = 0.77 in 46-54 years, P < 0.0001 for all]. This association was not significant in the oldest age group of 55-64 years. There was no significant association between opioid prescriptions and other categories of cannabis laws (recreational use and decriminalization) in any of the age groups studied.