Cardiovascular Risk and Marijuana Use

"Main findings

"24 studies evaluated the occurrence of MACE in the context of exposure to cannabis, including one to medical cannabis and none to other cannabinoids. The quantitative analysis suggests a positive association between cannabis use and MACE. Findings from the sensitivity analysis restricted to cohort studies were consistent with the primary analysis. These results cohere with other studies published outside of the time window of the present meta-analysis, including those from various cohorts in France or in the USA, respectively, showing an independent association between cannabis and in-hospital MACE,47 48 or between daily cannabis use and MI, stroke and the composite of coronary heart disease, MI and stroke.49 The only study on medical cannabis among those included in the meta-analysis also highlighted such a positive association.45

"Cerebrovascular disorders

"The studies centred on the assessment of stroke provide divergent results, whether suggesting or not a significant association between cannabis use and stroke. First, no association was found between cannabis use in young adulthood and early stroke (HR: 1.59, 0.59 to 4.28) in a study among a cohort of 50 000 men included during the compulsory military service in Sweden.35 In a case-control study among US adults younger than 50, the odds for stroke were found to be similar in subjects ever exposed to cannabis than in those never exposed.34 In both studies, estimation of exposure is likely biased since use of cannabis was measured at inclusion with no follow-up data in the first study; and the inclusion of single use over the lifetime in the second. No association was found in another cohort of US subjects included between the ages of 18 and 30 and followed up more than 25 years in the Coronary Artery Risk Development in Young Adults cohort (OR=0.57, 0.17 to 1.93).36 Age when cerebrovascular accidents occurred is not provided. Interestingly, no significant association was emphasised in the focused analysis on recent cannabis use, possibly due to a lack of power. Similar conclusions were provided from two additional studies among adults over 18 despite an overall adjustment on relevant covariables.31–33 In contrast, several studies within large cohorts found a higher risk of stroke in cannabis users, persistently significant after adjustment on relevant cardiovascular risk factors.23–25 28 Among those based on the exploration of the NIS, the largest database of US inpatients, the study by Vin-Raviv et al included all hospitalised patients (OR=1.60, 1.44 to 1.77), whereas in those by Kalla et al, Desai et al, Parekh et al and Rumalla et al, only patients under the age of 55 were included. In the latter study, ischaemic stroke was significantly associated with use of cannabis, with a marked increase in the 25–34 age range.28 The exploration of the PATH through life study cohort in Australia outlined that elevated stroke/transient ischaemic attack was specific to participants who used cannabis at least weekly (IRR=4.7, 2.1–10.7). Similarly, a higher proportion of stroke was emphasised only among subjects aged 18–74 who used cannabis frequently.

"Cardiac disorders

"Seven studies investigated the potential implication of cannabis in the occurrence of ACS, including five focused on acute MI, which demonstrated an independent association with the use of cannabis after adjustment for tobacco smoking and abuse of cocaine and amphetamine.37–41 In the study by Desai et al exploring the NIS database by millions of participants, the measured association was barely significant (OR=1.03, 1.02 to 1.05, p<0.001), raising the question of the clinical significance of statistically significant results.41 Three of the other four studies were also conducted on large electronic health databases,38–40 including that by Patel et al, which specifically explored this association in a younger population aged 15–22 (OR=1.36, 1.16 to 1.59). Similar results were found in a study examining the BRFSS: higher odds of acute MI were observed in patients who used cannabis more than once a week (OR=2.31, 1.18 to 4.50) but not in less frequent users (OR=1.48, 0.52 to 4.21).38 Surprisingly, the third study, which explored the French administrative hospital discharge database, concluded that among illicit drugs, cannabis was a predictor for MI, unlike cocaine and opioids.40 The authors hypothesise that their results lacked power due to the lower prevalence of cocaine and opioids than cannabis use in France. The non-significant association between the use of cocaine and MI may also illustrate the limitation of hospital databases to accurately measure exposure to illicit drugs. The fifth study highlighted a positive association within a small cohort of 85 men younger than 40.37 Considering the low number of included patients, caution is required to interpret the high OR value (OR=13.9, 3.4 to 57.1). Finally, one study specifically investigated the association between cannabis use and ACS in nearly 15 000 patients aged 18–54 and found no significant association in the overall sample but a higher risk in the subgroup of patients aged 18–36 (OR=5.24, IC 95% 1.85 to 16.94).42

"Cardiovascular mortality

"Cannabis use significantly increased all-cause mortality and cardiovascular mortality in a cohort of patients diagnosed with MI before the age of 50, after adjustment for age, cardiovascular risk factors including tobacco smoking and other health conditions.44 These findings are consistent with results from studies included in our previous review in which cannabis was statistically associated with increased middle-term but not long-term mortality in subjects with a history of acute MI.50 51 These were further supported by a more recent study exploring data from the NHANES which revealed a significant association between cannabis use and death from cardiovascular causes (HR=2.29, 1.10 to 4.78).43 No significant association was found for all-cause mortality (HR=1.14, 0.81 to 1.59).

"Interestingly, an analysis conducted in 2024 from the UK Biobank population emphasised a sex difference regarding cardiovascular mortality related to heavy cannabis use, with a significantly higher risk for women unlike men.52"