Marijuana Use May Increase Atherosclerosis Risk

Tobacco smoking is strongly associated with abdominal artery calcium (AAC) and coronary artery calcium (CAC) scores, according to a recent study. However, the risk for atherosclerosis is increased only among marijuana users who had ever used tobacco.

It is not currently known how marijuana smoke affects the risk for subclinical atherosclerosis and, in turn, the risk for cardiovascular disease (CVD).
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Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, researchers evaluated 3498 men and women who were aged 18 to 30 years at baseline (1985-1986). A total of 7 follow-up examinations were performed over the course of 25 years.

The researchers calculated cumulative years of exposure to marijuana, which was expressed in “marijuana years” (1 marijuana year = 365 days of use), with repeated assessments used every 2 to 5 years over 25 years. Computed tomography was used to determine AAC and CAC scores at Year 25.

Of the 3117 participants who had available AAC and CAC measurements, 2627 (84%) had reported past marijuana use, and 1536 (49%) had reported past daily tobacco smoking. A total of 46% of tobacco smokers reported 10 or more pack-years of use, while only 12% of marijuana users reported 5 or more marijuana-years of use, and only 6% reported using marijuana daily.

Results demonstrated a significant impact of ever-tobacco use on the association between cumulative marijuana use and AAC scores. Among ever-tobacco users, marijuana use was associated with AAC and CAC scores, at 5 marijuana-years of exposure with an odds ratio of 1.97 for an AAC score of more than 0 and a CAC score of 0, and 1.83 for a CAC score of more than 0. However, cumulative marijuana-years were not associated with AAC or CAC scores based on the results of adjusted models.

“Marijuana use appears to be associated with subclinical atherosclerosis, but only among ever tobacco users,” the researchers wrote.

—Christina Vogt

Reference:

Auer R, Sidney S, Goff D, et al. Lifetime marijuana use and subclinical atherosclerosis: the coronary artery risk development in young adults (CARDIA) study [Published online November 22, 2017]. Addiction. doi:10.1111/add.14110.