A population-based study in Ontario, Canada, found that neighborhoods located near cannabis retail stores had higher rates of cannabis-related emergency department visits than areas farther away, with the strongest effects in places where multiple stores were clustered within a small radius. The findings suggest that the density of cannabis outlets may influence community health risks after legalization.
Researchers from North York General Hospital and partner institutions analyzed data from 6,140,595 people living in Ontario, Canada, between the ages of 15 and 105 across 10,574 neighborhoods, covering the period from April 2017 through December 2022. The study, published in Annals of Internal Medicine, examined how nonmedical cannabis legalization in October 2018 and the subsequent expansion of retail stores were associated with neighborhood-level cannabis-related harms.
Using provincial records on cannabis store locations, the team defined exposure based on proximity to retailers. Neighborhoods were considered "exposed" if they were located within 1,000 meters of a cannabis retail store and "unexposed" if they were more than 1,000 meters away. The primary outcome was the rate of cannabis-attributable emergency department visits per 100,000 people aged 15 years or older.
According to the summary released by the American College of Physicians via ScienceDaily, exposed neighborhoods were more often located in major urban centers and were disproportionately represented in the lowest income quintile compared with unexposed areas. After a cannabis store opened nearby, exposed neighborhoods did not show an increase in their monthly rates of cannabis-attributable emergency department visits, while unexposed neighborhoods experienced a decline in these visits over the same time frame.
When the two groups were compared directly, neighborhoods exposed to nearby cannabis stores had a 12% increase in the absolute rate of cannabis-attributable emergency department visits relative to unexposed areas, with a 95% confidence interval of 6% to 19%. The researchers also found that neighborhoods with several cannabis stores located within 1,000 meters experienced greater increases in emergency visits than those with fewer nearby outlets.
The authors — Erik Loewen Friesen, Michael Pugliese, Rachael MacDonald-Spracklin, Doug Manuel, Kumanan Wilson, Erin Hobin, Andrew D. Pinto, and Daniel T. Myran — conclude that living near clusters of cannabis stores is associated with higher levels of cannabis-related harm. They suggest that limiting the overall number of retailers, reducing concentrated clusters, or restricting store locations in certain communities could help support public health goals in the context of legalized nonmedical cannabis.