Cannabis–fall link fades after accounting for cigarette smoking

Potential harms of preventable/modifiable use of substances, such as cannabis, among aging people with HIV (PWH) are unclear. We characterized longitudinal associations between current cannabis use and subsequent fall risk among aging PWH. Participants in the Advancing Clinical Therapeutics Globally (ACTG) A5322 study self-reported current cannabis use and any fall(s) annually and semiannually, respectively. Generalized linear models and inverse probability weighting were used to assess associations between cannabis use and subsequent fall risk, adjusting for baseline covariates (age, sex assigned at birth, and race/ethnicity), time-varying confounders, and study attrition. Among 957 participants (median age, 51 years), 18.2% reported current cannabis use at baseline; 18.6% reported falling in the first year of the longitudinal study. Current cannabis use was associated with moderate risk of any falls in the following year in baseline covariate-adjusted analysis (risk ratio [RR], 1.27 95% CI, 1.02, 1.57; P = .029), but not in analyses additionally adjusted for fall history, nonprescribed psychoactive substance use, psychotropic and analgesic medication use, heavy alcohol use, peripheral neuropathy, and cigarette smoking status (adjusted RR, 1.11 [95% CI, .83, 1.49]; P = .49). Cigarette smoking status was the main variable that attenuated the association between falls and cannabis use. Among aging PWH, the association between current cannabis use and fall risk was primarily confounded by cigarette smoking status. Future studies should incorporate more granular cannabis use data on falls risk, including cannabis composition or strain and dose.