Cannabis and synthetic cannabinoid poison control center cases among adults aged 50+, 2009-2019

Older (aged 50+) cannabis users are growing in numbers, but research on poison control center (PCC) cases has not focused on them. In this study, we examined: (1) changing trends in cannabis forms reported in PCC cases; (2) demographic and clinical factors associated with different cannabis forms; and (3) associations between cannabis forms and medical outcomes.

We used the American Association of Poison Control Centers' National Poison Data System (NPDS), January 1, 2009-December 31, 2019, to examine the 5201 cases aged 50+ in which cannabis was the only or primary substance. Following descriptive analyses, multinomial logistic regression was fit to examine associations of three cannabis forms (dried/undried plant, other preparations, and synthetic cannabinoids/e-cigarettes for cannabis delivery) with cases' demographic and clinical characteristics, and binary logistic regression was fit to examine associations of medical outcomes (major/potentially major vs. nonmajor) with cannabis forms.

Cannabis-related cases involving older adults increased 18-fold (from 61 to 1074) between 2009 and 2019. Compared to plant forms, other preparations had 51.24 times greater odds of appearing in 2018-2019 than in 2009-2011 (95% CI = 27.74-94.67), and synthetic cannabinoids/e-cigarettes had 2.19 times greater odds of appearing in 2014-2015 (95% CI = 1.64-2.93) but lower odds of appearing in 2016-2017 (RRR = 0.67, 95% CI = 0.50-0.89). Other preparations were positively associated with older age, adverse reactions, and suicide attempts but negatively associated with medical cannabis legal states. Synthetic cannabinoids/e-cigarettes were positively associated with being male, intentional misuse/abuse, and chronic use. Compared to plant forms, major medical outcomes/death were less likely among those who used other preparations (OR = 0.75, 95% CI = 0.56-0.99) but more likely among those who used synthetic cannabinoids/e-cigarettes (OR = 2.07, 95% CI = 1.60-2.66).

Although PCC cannabis cases involving older adults are relatively few, cases of other cannabis preparations than plant forms increased rapidly in recent years while cases of synthetic cannabinoids decreased. The rate of major medical outcomes also appears to be high.