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Abstract
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In October 2018, Canada legalized the sale of dried cannabis flowers for nonmedical use, and in January 2020, edible cannabis became legally available for retail.1 In California, legalization of all forms of nonmedical cannabis has been associated with increased cannabis-related emergencies in older adults (aged ≥65 years).2 Limited information exists on the specific health outcomes of nonmedical edible cannabis use in older adults3; thus, we examined the association between edible cannabis legalization and emergency department (ED) visits for cannabis poisoning in older adults residing in Ontario, Canada.
Methods
This retrospective, population-based, cross-sectional study was approved by the Sunnybrook Health Sciences Centre research ethics board, which waived the need for informed consent because all data were deidentified. This study followed the STROBE reporting guideline.
We used linked Ontario Ministry of Health administrative data to examine ED visit rates for cannabis poisoning in older adults during 3 policy periods: prelegalization (January 2015 to September 2018); legalization period 1, which permitted the sale of dried cannabis flowers only (October 2018 to December 2019); and legalization period 2, which also permitted the sale of edible cannabis (January 2020 to December 2022). We identified ED visits where cannabis poisoning was the main or contributing reason (eAppendix in Supplement 1) and calculated rates per 100 000 person-years for older adults. We calculated incidence rate ratios (IRRs) using a Poisson regression model and 3-level categorical variable for each policy period. We adjusted models for age, sex, rurality, neighborhood income quintile, alcohol intoxication, cancer diagnosis, and dementia diagnosis (eAppendix in the Supplement). Data on race and ethnicity were unavailable. A 2-tailed type I error rate of.05 was the threshold for statistical significance. Statistical analyses were conducted using SAS, version 9.4 (SAS Institute, Inc).
Results
During the 8-year study period, there were 2322 ED visits for cannabis poisoning in older adults (1041 women [44.8%]; 1281 men [55.2%]; median [IQR] age, 69.5 [67.3-73.8] years). Among patients with cannabis poisoning, 385 (16.6%) had concomitant alcohol intoxication, 895 (38.5%) cancer, and 151 (6.5%) dementia.
During legalization period 1, the rate of ED visits was substantially higher than prelegalization (15.4 vs 5.8 per 100 000 person-years; adjusted IRR, 2.00; 95% CI, 1.29-3.10) (Figure; Table). During legalization period 2, the rate of ED visits (21.1 per 100 000 person-years) was significantly greater than prelegalization (adjusted IRR, 3.08; 95% CI, 2.04-4.65).
Discussion
In this study, cannabis legalization in Canada was associated with increased rates of ED visits for cannabis poisoning in older adults. The largest increases occurred after edible cannabis became legally available for retail sale, a phenomenon similarly observed in Canadian children.4 Possible explanations include increases in accidental ingestion; ease of access; lack of age-specific dosing instructions; and absence of safe and effective treatment options for chronic pain, sleep disturbances, and behavioral and psychological symptoms of dementia. Older adults are at particularly high risk of adverse effects from cannabis due to age-related physiological changes, polypharmacy, drug interactions, and multimorbidity. ...
Language: en |