A study which tracked more than 4000 US veterans over three years has found that those with a history of smoking cannabis were less likely to be affected by cardiovascular issues such as heart attacks, stroke, and cardiovascular death than those who hadn’t previously smoked cannabis.
Researchers claim it is the first “well-powered” study to evaluate the link between self-reported cannabis use and the risk of long-term cardiovascular disease.
“To our knowledge, the current study is the only study to examine the association of cannabis use with longitudinal cardiovascular disease outcomes among persons with established coronary artery disease (CAD).”
The research, published in the journal Circulation, followed 4,285 military veterans aged 66-68 with CAD. Of these, 1,015 reported using cannabis within the past three months, with 510 using it daily.
Researchers hypothesised at the beginning of the study that smoking cannabis would carry an added risk of longitudinal cardiovascular disease. They based their hypothesis on the “biological plausibility” that smoking cannabis would carry the same risk to health as smoking tobacco, and on data from previous studies that found cannabis use to be “associated with adverse cardiovascular outcomes, with heavier use (more days per month) associated with higher odds of adverse outcomes.”
During a 3.3-year follow-up period, 563 participants experienced major cardiovascular events, including heart attacks, strokes or cardiovascular death. However, researchers found no statistical difference in event rates between cannabis users and non-users.
“In this cohort of older veterans with coronary artery disease, self-reported cannabis use was not independently associated with increased cardiovascular events,” the study authors said.
Researchers from the University of California found that those in the cohort who had used cannabis recently had a lower prevalence of comorbid conditions than those who hadn’t. For instance, they were less likely to be affected by hypertension (81% versus 85%), hyperlipidemia (69% versus 79%), percutaneous coronary intervention (15% versus 20%), previous AMI (heart attacks) (16% versus 19%), heart failure (17% versus 24%), and atrial fibrillation (13% versus 18%).
In contrast, participants who used cannabis were more likely to be less healthy in other aspects of their lives and enjoy a lower socio-economic status than non-cannabis smokers.
For instance, “adults who smoked cannabis were less likely to be married (40% versus 53%), more commonly lived alone (37% versus 30%), and more commonly reported that “paying for basics was hard or very hard” (23% versus 16%) compared with adults who did not use cannabis in the previous 30 days. Adults who smoked cannabis also reported higher prevalence of current tobacco use (46% versus 26%) and severe alcohol misuse (9.3% versus 3.5%). About 5% of adults who smoked cannabis were lifetime nontobacco users versus 11% of adults who did not smoke cannabis in the past 30 days. Although past 30-day substance use (other than cannabis use) was infrequent in this older cohort, former substance use was more common among adults who smoked cannabis (59% versus 29%) compared with those who did not smoke cannabis.”, stated the study.
Despite adjusting for comorbidities and socioeconomic circumstances, researchers found no association between smoking cannabis and longitudinal cardiovascular disease risk, but called for further research to be conducted.
“In conclusion, we did not observe an association between smoking cannabis and cardiovascular events among this older cohort of veterans with CAD and a significant history of lifetime tobacco use,” the study authors said. “Future cohort studies of adults in a more general population sample and those with lifetime tobacco nonuse are needed to further examine the association of cannabis use with cardiovascular events.”
