Research: #Cannabis Smoke Much Less Harmful Than #Tobacco Smoke

Researchers publishing their findings of a 25-year international research project involving over 5000 people in the 22 November 2017 in the Journal “Addiction” have concluded that periodic marijuana smoking is not associated the cardiovascular disease.

However, they note that regular marijuana smoking does increase risk.

Since 1985, the U.S. National Heart, Lung and Blood Institute has funded the Coronary Artery Risk Development in Young Adults (CARDIA) study, and has been following over 5,000 participants beginning in early adulthood from across the United States, with sites in Birmingham, AL, Chicago, IL, Minneapolis, MN, and Oakland, CA, to measure coronary and abdominal artery calcium build-up with CT (Computed Tomography) scan of tobacco and marijuana smokers.

Reto Auer at the University of Bern Institute for Primary Health Care led an international team of researchers in analysing data on 3,498 men and women who participated in the 25-year US‐based Coronary Artery Risk Development in Young Adults (CARDIA) study. The University of Bern is located in Bern, Switzerland.

The longitudinal CARDIA study included 25 years of multiple of measures of marijuana and tobacco exposure, starting in early adulthood. In the 25th year, CARDIA measured coronary and abdominal artery calcium with computed tomography.

Cumulative marijuana use was not associated with plaque build-up in middle-aged adults never exposed to tobacco, but in contrast, researchers found an increased risk of atherosclerosis among those with very high marijuana exposure.

“Compared with tobacco smokers, 46% of whom reported 10 or more pack‐years of use, only 12% of marijuana users reported 5 or more marijuana‐years of use and only 6% reported having used marijuana daily.”
– Research published 22November2017

Conclusion: Marijuana use appears to be associated with subclinical atherosclerosis, but only among ever tobacco users.

See: https://onlinelibrary.wiley.com/doi/full/10.1111/add.14110

Auer, R., Sidney, S., Goff, D., Vittinghoff, E., Pletcher, M.J., Allen, N.B., Reis, J.P., Lewis, C.E., Carr, J., Rana, J.S., 2017. Lifetime Marijuana Use and Subclinical Atherosclerosis: The Coronary Artery Risk Development in Young Adults (CARDIA) Study. Addiction. [epub ahead of print] https://onlinelibrary.wiley.com/doi/full/10.1111/add.14110