A new study has called for urgent research into the health effects of cannabis when not used for medical purposes.
Two new preliminary studies – to be published in the journal Stroke – have suggested that cannabis use links to stroke risk in young people.
Links have also been made between those who have a cannabis use disorder – characterised by frequent, compulsive use of marijuana, similar to alcoholism – and increased likelihood of heart rhythm disturbances (arrhythmias).
Robert Harrington, president of the American Heart Association and the Arthur L. Bloomfield professor of medicine at Stanford University in Stanford, California, said: “As these products become increasingly used across the country, getting clearer, scientifically rigorous data is going to be important as we try to understand the overall health effects of cannabis.”
Stroke risk in young people
The data revealed that young people who were frequent cannabis users, and who also smoked cigarettes or e-cigarettes, were three times more likely to have a stroke compared to non-users, and that those who used cannabis for 10 days or more were 2.5 times more likely to have a stroke compared to those that did not smoke cannabis.
The study noted that although it shows cannabis use links to stroke, cannabis users were also more likely to be heavy drinkers, current cigarette users and e-cigarette users, which may have also influenced their risk – the researchers adjusted for those factors.
Lead study author Tarang Parekh, a health policy researcher at George Mason University in Fairfax, Virginia, said: “Young cannabis users, especially those who use tobacco and have other risk factors for strokes, such as high blood pressure, should understand that they may be raising their risk of having a stroke at a young age.
“Physicians should ask patients if they use cannabis and counsel them about its potential stroke risk as part of regular doctor visits.”
The study identified a potential link rather than proving a cause and effect as it was observational and did not examine the biological mechanism connection between stroke and cannabis use.
Heart risk in young people
Young people who were had cannabis use disorder increased their risk of poor heart health – an arrythmia – by 50% compared to those that did not use cannabis.
While some arrhythmias are benign, others can be life-threatening.
Rikinkumar S. Patel, resident physician in the department of psychiatry at the Griffin Memorial Hospital in Norman, Oklahoma, said: “The effects of using cannabis are seen within 15 minutes and last for around three hours. At lower doses, it is linked to a rapid heartbeat. At higher doses, it is linked to a too-slow heartbeat.
“The risk of cannabis use linked to arrhythmia in young people is a major concern, and physicians should ask patients hospitalised with arrhythmias about their use of cannabis and other substances because they could be triggering their arrhythmias.
“As medical and recreational cannabis is legalised in many states, it is important to know the difference between therapeutic cannabis dosing for medical purposes and the consequences of cannabis abuse.
“We urgently need additional research to understand these issues.”
In this study, young African American men with cannabis use disorder, between 15 to 24 years of age, had the greatest risk of being hospitalised for arrhythmia, although cannabis use disorder was more common among white men, 45 to 54 years of age.
Data for this study was derived from the Agency for Healthcare Research and Quality’s Nationwide Inpatient Sample, and this is the first, large-scale, population-based study to evaluate a link between cannabis use disorder and hospitalisation for arrhythmias. Although it does not prove cause and effect, it establishes an important trend.