Aging
Differences in Global Cognition by Marijuana Use in Older Adults Participating in the Health and Retirement Study Nikhil Mullapudi* Nikhil Mullapudi UCSF
Background: With the growing rates of recreational marijuana use among older adults in the US, a deeper understanding of the impacts of marijuana use on the aging brain grows as well. Amid conflicting evidence regarding the cognitive effects of marijuana use, this study examines differences in later-life cognition by marijuana use in a nationally representative sample of older adults.
Methods: 1,309 respondents from the 2018 wave of the Health and Retirement Study (HRS) were included in this retrospective cross-sectional study. Respondent’s marijuana use was categorized as never (65.9%), former (no use in past 5 years; 21%), or recent (use within 5 years; 13.1%). Global cognition was assessed using the HRS version of the Telephone Interview for Cognitive Status (TICS), which provides a score from 0 to 27, where higher scores indicate better cognitive function. A linear regression model was employed to investigate differences in total cognition by marijuana use category. Demographics, other comorbidities, and alcohol/tobacco use were included as covariates in the model.
Results: Study participants had a mean age of 67.1 (10.6) years, 58.7% were female, and 67% identified as white. Mean TICS scores were 1.21 points higher in former users (mean = 16.4), and 0.84 points higher in recent users (mean = 16.0), compared to never users (mean = 15.2). In fully adjusted models, former users had significantly higher TICS scores than never users (B = 1.67, p = 0.01, 95% CI [0.39, 2.96]), but did not differ for recent users (B = 0.05, p = 0.95, 95%CI [-1.60, 1.70]), compared to never users.
Conclusions: Among older adults in the 2018 HRS, former marijuana users had slightly better global cognitive function than never users, while recent and never users did not differ significantly. Although additional studies are needed to determine whether this association is causal, these findings suggest that past marijuana use may be associated with preserved later-life cognition.