The Coronary Artery Risk Development in Young Adults (CARDIA) Study.

BACKGROUND

Resting heart rate can predict cardiovascular disease. Heart rate increases with tobacco smoking, but its association with cannabis use is unclear. We studied the association between current and cumulative cannabis use and heart rate.

METHODS

We used data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a large prospective cohort of 5115 Black and white women and men followed over 30 years. We explored the association between cannabis exposure and heart rate, adjusted for demographic factors, cardiovascular risk factors, alcohol and other illicit drug use, physical activity, and beta-blockers, in mixed longitudinal models censoring participants with cardiovascular disease.

RESULTS

CARDIA participants contributed to 35,654 individual examinations over 30 years. At the Year 30 examination, 471 out of 3269 (14%) currently used cannabis. In multivariable adjusted models, compared to no current use, using cannabis 5 times per month was associated with lower heart rate of -0.7 beats per minute (95% confidence interval: -1.0 to -0.3), and daily use with lower heart rate of -2.1 beats per minute (95% confidence interval: -3.0 to -1.3, overall P < .001). Cumulative exposure to cannabis use was not associated with heart rate.

CONCLUSION

Recent current cannabis use was associated with lower resting heart rate. The findings appeared to be transient because past cumulative exposure to cannabis was not associated with heart rate. This adds to the growing body of evidence suggesting a lack of deleterious association of cannabis use at a level typical of the general population on surrogate outcomes of cardiovascular disease.