History of Cannabis Smoking and Subjective Cognitive Complaints in Older Women

Cannabis use has been increasing in the USA, yet its potential long-term effects on neurocognitive outcomes remain unknown. We aimed to examine the association of the history of cannabis smoking with subjective cognitive complaints (SCC) in older women.

This prospective cohort analysis included 15,378 older women (age ≥65 years) of the USA from the National Institute of Environmental Health Sciences' Sister Study. Participants reported their history of cannabis smoking at enrollment (2003-2009) and completed the Eight-item Interview to Differentiate Aging and Dementia (AD8) as an SCC screener at the cohort's 2nd (2011-2014), 3rd (2014-2016), and 4th (2017-2019) follow-ups. We used multivariable joint models to assess the association.

Overall, 3,973 (25.8%) women reported ever smoking cannabis, mostly in their early adulthood. Compared with never cannabis smokers, the multivariable odds ratios (ORs) for ever smokers were 1.27 (95% confidence interval [CI]: 1.13, 1.43) at the 2nd follow-up, 1.28 (95% CI: 1.14, 1.44) at the 3rd follow-up, and 1.30 (95% CI: 1.11, 1.52) at the 4th follow-up. Associations were stronger for regular than occasional cannabis smokers. For example, at the 2nd follow-up, the OR was 1.61 (95% CI: 1.31, 1.98) for regular smokers and 1.19 (95% CI: 1.04, 1.35) for occasional smokers. Results were overall consistent in subgroup and sensitivity analyses.

This study suggests a potential association between a history of cannabis smoking and SCC in older women, calling for further research on cannabis use and cognitive outcomes in the context of aging.