Marijuana use among older adults has increased over the past decade.
Describe marijuana use and driving outcomes among older drivers in Colorado, which has legalized medical and recreational use.
We examined the association of self-reported past-year marijuana use and driving outcomes in 598 drivers aged 65–79 (mean 70.6 years; 51 percent female, 70 percent postsecondary education), using regression analysis to adjust for health and sociodemographic characteristics.
244 (40.7 percent) drivers reported ever using marijuana. Fifty-four (9.0 percent) reported past-year use, ranging from at least weekly (33.4 percent) to less than monthly (50.0 percent). Only five participants (0.8 percent) reported using marijuana within 1 hour of driving in the past year. Past-year users were younger, less educated and lower income, and reported significantly worse mental, emotional, social and cognitive health status, compared to those without past-year use. Past-year users were four times as likely to report having driven when they may have been over the legal blood-alcohol limit (adjusted OR [aOR]=4.1; 95 percent CI: 2.0, 8.2) but were not more likely to report having had a crash or police action (e.g., being pulled over) (aOR=1.4 [0.7, 2.7]) in the past year. An index of driving-related lapses, errors and violations in the past year was also similar among users and non-users (adjusted beta=0.04 [-0.04, 0.12]).
Nearly 10 percent of Colorado drivers aged 65–79 reported past-year marijuana use, but driving immediately after use was uncommon. Despite significantly worse mental, emotional and social health and increased driving while alcohol-impaired, past-year marijuana use was not associated with more frequent self-reported lapses, errors and violations or motor vehicle crashes and police actions.
While driving under the influence of marijuana appears to be rare in older drivers, further study is needed to establish driving risks resulting from marijuana use, independent of other associated risk factors.