Cumulative Marijuana Use NOT Associated With Heart Abnormalities

According to a new study published in the journal Addiction, neither the current nor the cumulative lifetime use of marijuana is associated with heart abnormalities at middle age. The study, first reported on by NORML, is titled Association between marijuana use and electrocardiographic abnormalities by middle age.

For the study researchers from Switzerland and the United States examined the relationship between cumulative marijuana use and the prevalence of electrocardiogram (ECG) abnormalities in a group of 2,585 middle age subjects. “Researchers controlled for several potential confounders, including subjects’ use of alcohol and tobacco, as well as blood pressure and cholesterol levels.”

Investigators reported: “We found no evidence that current or lifetime cumulative use of marijuana was associated with a higher prevalence or incidence of major or minor ECG abnormalities in this cohort, … although major ECG abnormalities seemed to be less frequent in current marijuana users. … Whether participants used marijuana daily, in the last 30 days or intermittently over a lifetime, marijuana use was not associated with an increase in prevalent or incident specific ECG abnormalities by middle-age.”

They concluded by stating that “Our finding that occasional marijuana was not associated with ECG abnormalities adds to the growing body of evidence that this level of marijuana use and CVD [cardiovascular disease] events and markers of subclinical atherosclerosis are not associated.”

The full abstract of this study can be found below:

Aims: To evaluate the prevalence of electrocardiogram (ECG) abnormalities in marijuana users as an indirect measure of subclinical cardiovascular disease (CVD).

Design: Longitudinal and cross-sectional secondary data analysis from the CARDIA (Coronary Artery Risk Development in Young Adults) study.

Setting: 4 communities in the United States.

Participants: A total of 2,585 participants from the 5,115 black and white men and women recruited at age 18 to 30 years in 1985 to 1986 in CARDIA.

Measurements: ECG abnormalities coded as minor and major abnormalities with the Minnesota code of electrocardiographic findings at Year 20. Self-reported current (past 30 days) and computed cumulative lifetime marijuana use (one “marijuana-year” corresponds to 365 days of use) through assessments every 2-5 years. We fitted logistic regression models adjusting for sex, race, center, education, age, tobacco smoking, physical activity, alcohol use, and body mass index.

Findings: Among the 2,585 participants with an ECG at Year 20, mean age was 46, 57% were women, 45% were black. 83% had past exposure to marijuana and 11% were using marijuana currently. One hundred and seventy-three participants (7%) had major abnormalities and 944 (37%) had minor abnormalities. Comparing current with never use in multivariable-adjusted models, the OR for major ECG abnormalities was 0.60 (95% CI: 0.32 to 1.15) and for minor ECG abnormalities 1.21 (95% CI: 0.87 to 1.68). Results did not change after stratifying by sex and race. Cumulative marijuana use was not associated with ECG abnormalities.

Conclusion: In a middle-aged US population, lifetime cumulative and occasional current marijuana use were not associated with increases in electrocardiogram abnormalities. This adds to the growing body of evidence that occasional marijuana use and cardiovascular disease events and markers of subclinical atherosclerosis are not associated.