Abstract P131: Association between Marijuana Exposure and Cognitive Function in Middle Age: the Coronary Artery Risk Development in Young Adults (CARDIA) study.
Background: Smoking marijuana is increasingly common, and understanding whether it is associated with long-term cognitive dysfunction has important implications for public health messaging.
Aims: We estimated associations between cumulative exposure to marijuana and cognitive function (CF), adjusted for current marijuana use, cigarette smoking and other determinants of CF.
Methods: Participants in the CARDIA Study, a population-based study of African Americans and European Americans recruited in 1985/6 at age 18-30 and followed over 25 years. Marijuana use was assessed at clinical visits at years 0, 2, 5, 7, 10, 15, 20 and 25 (2010/11); and cigarette smoking each year. Lifetime exposure to marijuana was expressed in joint-years, with 1 joint-year equivalent to smoking 365 joints. CF at year 25 was assessed with the Rey Auditory Verbal Learning Test (RAVLT), the Digit Symbol Substitution Test (DSST) and the Stroop Interference Test, each expressed as standardized z-scores. We estimated associations between current and lifetime marijuana exposure and each CF score using linear regressions, adjusted for baseline demographics, current smoking and diabetes and cumulative exposure to cigarette smoking, alcohol, illicit drugs, cardiovascular risk factors, physical activity and depression (see Table footnote).
Results: Of 3385 participants with CF data, 24% had never reported marijuana use, 43% had smoked <0.5 joint-year during their lifetime, 22% 0.5 to 5 joint-years and 11% ≥5 joint-years; 9% had smoked marijuana within the last 30 days. In adjusted models, current marijuana use was significantly associated with a worse RAVLT test score, but we found no association between cumulative exposure to marijuana use and CF (Table). In contrast, current and cumulative exposure to cigarette smoking were associated with lower CF.
Conclusion: Cigarette smoking (current and cumulative) and current marijuana use are associated with lower CF, but we found no evidence of an association with cumulative lifetime exposure of marijuana on CF.
Author Disclosures: R. Auer: None. E. Vittinghoff: None. K. Yaffe: None. S.G. Kertesz: None. D.A. Levine: None. S. Sidney: None. M. Glymour: None. M.J. Pletcher: None.
- © 2014 by American Heart Association, Inc.