As cannabis legalization continues to spread globally, concerns about its health effects have grown. Two recent studies highlight a significant risk for heart health among cannabis users. A retrospective study published in JACC Advances and a meta-analysis presented at the American College of Cardiology’s Annual Scientific Session both reveal that cannabis use is associated with a markedly higher risk of heart attack.

Retrospective Study: A Sixfold Increase in Heart Attack Risk

The retrospective study utilized patient data from TriNetX, a global health research network providing access to electronic medical records. Researchers followed patients under 50 years old, with no cardiovascular history, for over three years. Surprisingly, cannabis users were found to have a six times higher risk of experiencing a heart attack compared to non-users.

Related News

Moreover, the study identified other cardiovascular risks for cannabis users:

  • Four times higher risk of ischemic stroke (caused by blood clots or plaque blocking blood flow to the brain)
  • Two times higher risk of heart failure
  • Three times higher risk of cardiovascular death, heart attack, or stroke

Participants in this study were free from diabetes, coronary artery disease, and tobacco use at the start. They maintained healthy blood pressure and LDL cholesterol levels, indicating that cannabis use alone could significantly impact heart health.

Meta-Analysis: A 50% Increased Risk

The meta-analysis pooled data from 12 studies, involving over 93,000 cannabis users and 4.5 million non-users, making it the most extensive study of its kind. The average age across these studies was 41 years, though some studies lacked age details.

Out of the 12 studies, seven reported an increased heart attack risk for cannabis users, four found no significant difference, and one observed a slightly lower risk among users. When combining all data, the analysis concluded that cannabis users have a 50% higher risk of heart attack compared to non-users.

One study within this analysis noted that the heart attack risk peaks about one hour after cannabis use, indicating an acute effect. However, the meta-analysis couldn’t account for factors like the amount and duration of cannabis use or concurrent tobacco or drug use due to data limitations.

Expert Opinions: Cardiovascular Risks and Cannabis Use

Dr. Ibrahim Kamel, the retrospective study’s lead author, emphasized the need for clinicians to inquire about cannabis use as part of cardiovascular risk assessments, akin to smoking history. He stressed that individuals should be informed about the potential cardiovascular risks associated with cannabis use.

Dr. Hoang Nguyen, an interventional cardiologist not involved in the study, noted the confounding factor of other drug use. For example, substances like cocaine are known to increase heart attack risk and weaken heart muscles, leading to heart failure.

Inhalation vs. Ingestion: Which Poses Greater Risk?

A critical gap in both studies is the inability to differentiate between inhaled and ingested cannabis’s effects on heart health. Dr. Kamel suggested that future research should investigate the risks of inhaled cannabis versus edible forms like brownies or gummies.

Dr. Andrew Meltzer, an emergency medicine professor, highlighted that while tobacco inhalation’s respiratory risks are well-documented, cannabis inhalation’s long-term effects remain unclear. Chronic inhalation may impact lung health and could similarly affect cardiovascular function, but more studies are needed.

Is Any Cannabis Use Safe?

Dr. Kamel acknowledged the challenge in determining a “safe” amount of cannabis without extensive clinical trials. However, he confirmed that a cardiovascular risk exists, even if the exact threshold of safe use remains unclear.

Dr. Nguyen suggested that frequency and dosage might influence risk levels, but emphasized the need for more comprehensive research. Meanwhile, Dr. Sameer Amin, a cardiologist, advised avoiding substances that elevate cardiovascular disease risk altogether.

Dr. Meltzer noted that occasional, low-dose cannabis use is generally benign. For instance, in chemotherapy patients, short cannabis doses reduce nausea and stimulate appetite. However, chronic use can lead to adverse effects like cannabinoid hyperemesis syndrome, characterized by nausea and abdominal discomfort—a costly public health concern.

Public Health Concerns and the Need for Further Research

As cannabis legalization expands, the ongoing situation is likened to a public health experiment. Dr. Meltzer stressed the importance of continued monitoring of cannabis’s health effects to avoid unforeseen long-term consequences.

Both studies highlight the urgent need for further investigation into cannabis’s cardiovascular effects, especially as legal access increases. Researchers must explore the mechanisms by which cannabis affects heart rhythm, oxygen demand, and arterial function.

Mechanisms Behind Cardiovascular Risks

Researchers speculate that cannabis may:

  • Affect heart rhythm regulation
  • Increase myocardial oxygen demand
  • Contribute to arterial lining dysfunction, impairing blood vessel relaxation and expansion, potentially interrupting blood flow

These factors can increase the likelihood of heart attacks, particularly in users with other cardiovascular risk factors.

Future Directions and Recommendations

Given these findings, healthcare providers should integrate cannabis use inquiries into cardiovascular risk assessments. Public health initiatives should inform users about the potential heart risks associated with cannabis use.

Patients, particularly those under 50 and without cardiovascular issues, should be cautious about cannabis use. Regular cardiovascular check-ups and honest communication with healthcare providers about cannabis use are crucial.

These studies underscore a significant concern: cannabis use may substantially increase the risk of heart attack and other cardiovascular events. While cannabis offers therapeutic benefits, especially for chemotherapy patients, its potential cardiovascular risks cannot be ignored.

As cannabis legalization grows, so does the need for robust research to understand its health implications fully. Users should stay informed and consult healthcare professionals to make well-informed decisions about cannabis use and heart health.