Cannabis use detrimental to heart health

Cannabis users may be putting themselves at risk of adverse cardiovascular outcomes, with the risk increasing proportionately with the frequency of use.

A large study that involved 434,104 adults (mean age 45.4 years, 51.1 percent women, 60.2 percent White) in the general US population showed that compared with nonuse, daily cannabis use had no significant effect on coronary heart disease (CHD) but was associated with greater odds of myocardial infarction (MI; adjusted odds ratio [aOR], 1.25, 95 percent confidence interval [CI], 1.07–1.46) and stroke (aOR, 1.42, 95 percent CI, 1.20–1.68), as well as the composite of CHD, MI, and stroke (aOR, 1.28, 95 percent CI, 1.13–1.44). [J Am Heart Assoc 2024;doi:10.1161/JAHA.123.030178]

Less frequent use (nondaily) was associated with a lower but still elevated estimated ORs for the studied outcomes relative to daily cannabis use.

The investigators, led by Dr Abra Jeffers of Massachusetts General Hospital in Boston, Massachusetts, US, highlighted other important findings. First was the absence of a significant interaction between cannabis and tobacco use, which meant that exposure to either substance contributed independently to the risk of adverse cardiovascular outcomes. This was further supported by the observed association between cannabis use and cardiovascular events among individuals who never used tobacco.

Meanwhile, the link between cannabis use and adverse cardiovascular outcomes was stronger among younger adults (defined as men younger than 55 years and women younger than 65 years) at increased risk of premature cardiovascular disease.

Results were consistent across various sensitivity analyses, including restricting the sample to daily cannabis users and nonusers, using propensity score matching, and applying different statistical models, they said.

All participants included in the study completed the BRFSS* cannabis module. The weighted prevalence of daily cannabis use was 4.0 percent, while that of nondaily use and nonuse was 7.1 percent and 88.9 percent, respectively. The median frequency of cannabis use among users was 5 days per month, with smoking being the most common form of cannabis consumption (73.8 percent of current users). Most of the participants had never used tobacco cigarettes (61.1 percent).

The prevalence rates of CHD, MI, stroke, and the composite outcome of all three were 3.5 percent, 3.6 percent, 2.8 percent, and 7.4 percent, respectively.

Cannabis and tobacco effects

“The independent effects of cannabis and tobacco cigarette use in the general adult population and effects of cannabis use among those who never used tobacco cigarettes are notable, because some have questioned whether cannabis use has any effect beyond that of being associated with tobacco use, despite the shared mechanism of inhaling particulate matter,” Jeffers said. [Stroke 2017;48:265-270; Stroke 2017;48:e132; J Am Coll Cardiol 2018;72:1559-1560]

“Cannabis smoke is not all that different from tobacco smoke, except for the psychoactive drug: tetrahydrocannabinol vs nicotine. Our study shows that smoking cannabis has significant cardiovascular risks, just like smoking tobacco,” he pointed out.

The findings have important clinical implications, given that cannabis use is increasing, and conventional tobacco use is decreasing, according to Jeffers. Such a trend coincides with a concerning shift in public perception, with people increasingly underestimating the harmfulness of cannabis use, he added.

“Patients should be screened for cannabis use and advised to avoid smoking cannabis to reduce their risk of premature cardiovascular disease and cardiac events,” Jeffers said.

* Behavioral Risk Factor Surveillance System Survey