Smoking marijuana regularly may raise the risk of potentially-deadly irregular heartbeats, a study suggests.
Cannabis users were 35 per cent more likely to be diagnosed with atrial fibrillation within a decade compared to non-users.
Researchers believe the culprit is poisonous byproducts of inhaling toxic smoke.
The heart condition is the most common type of treated heart arrhythmia that can lead to stroke, heart failure, and other heart-related complications.
At least 2.7 million Americans are living with the irregular heartbeat, though it can often go undiagnosed because many people do not experience symptoms.
The latest study, which included data from 23 million patients also looked at the risk of heart arrhythmias among users of other drugs.
Cocaine users were 61 per cent more likely to develop AF than people who did not use the drug.
People who used opiates, which can include heroin and prescription drugs, were at 74 per cent increased risk of developing the severe arrhythmia.
Cannabis users were 35 per cent more likely to develop AF compared to people who do not use the drug. Researchers behind the the new study attribute the negative health effects to inhaling toxic particles.
People who used any of the four studied drugs were far more vulnerable to developing atrial fibrillation compared to the control group at baseline who did not use any drugs, represented here. People who used methamphetamine were at the highest risk.
Atrial fibrillation is a common form of cardiac arrhythmia. It occurs when the heart’s upper chambers (atria) beat out of sync with the lower chambers (ventricles). It can lead to myriad heart conditions as well as blood clotting which increases the risk of stroke.
The report, authored by researchers at the University of California San Francisco, was published in the European Heart Journal.
They write: ‘Despite exhibiting a weaker association with incident AF than the other substances, cannabis use still exhibited an association of similar or greater magnitude to risk factors like dyslipidemia, diabetes mellitus, and chronic kidney disease.’
‘Furthermore, those with cannabis use exhibited similar relative risk of incident AF as those with traditional tobacco use,’ they said.
In cases of atrial fibrillation, the upper chambers of the heart, or the atria, beat chaotically and out of sync with the lower chambers, or ventricles, of the heart.
Researchers analyzed data from every hospital admission and every visit to outpatient surgical facilities and emergency departments in California from 2005 through 2015, collecting information from a total of 23 million people.
Just a fraction of patients included in the study used drugs: 132,834 used cannabis, 98,271 used methamphetamine, 48,700 used cocaine, and 10,032 used opiates.
Marijuana is the third-most commonly used drug in the US behind alcohol and tobacco, and its prevalence is growing as more states embrace its therapeutic and medicinal properties.
What are the health risks of marijuana?
About 48million Americans smoke cannabis at least once a year, official estimates suggest.
This figure is rising as states continue to legalize the drug.
But evidence is also growing over its health risks, particularly for young adults.
Researchers suggest it has the following negative impacts:
- Brain damage: It can cause a permanent loss of IQ and even alter development in young adults;
- Mental health: It has been linked to suicide, depression and anxiety in the past, although it is unclear if marijuana is the cause;
- Daily life: Surveys link it to more problems in careers and relationships;
- Driving: Those who drive under the influence have slower reactions and less coordination, research shows.
Source: Substance Abuse and Mental Health Services Administration.
More than 48 million Americans try marijuana annually — or 18 per cent of the population. About nine per cent of first-time cannabis users become drug-dependent within a decade.
Meanwhile, it has been legalized for recreational use in 19 states so far, with others such as North Dakota eyeing their own legalization measures in this year’s midterms.
The UCSF study was not meant to dissect the individual components of marijuana use, or any other drug’s use, that may lead to atrial fibrillation. But the researchers posit that inhaled particulates are a likely factor.
Principal investigator Dr Gregory Marcus, a UCSF professor of Medicine with the Division of Cardiology said: ‘It’s also intriguing to consider that inhaled substances travel directly from the lungs to pulmonary veins, which empty into the left atrium, and that the pulmonary veins and the left atrium are especially important in generating AF.’
Typically, seniors are at the greatest risk for developing AF.
Stimulants such as cocaine and methamphetamine have a stronger link to cardiovascular conditions because they prompt the heart to beat faster and with greater force, raising blood pressure to dangerous heights.
While long-term risks associated with marijuana use have been found to include chronic lung issues and cognitive impairment, especially among young people whose brains are still developing.
A large study conducted in 2012 in New Zealand found that persistent marijuana consumption starting in adolescence was associated with a loss of an average of 6 or up to 8 IQ points measured in mid-adulthood.
Many people consume marijuana with the theory that it will boost their creativity, though the science backing up that claim is dubious.
A recent study conducted by University of Washington researchers was recently published in which 400 participants took a creativity test either 15 minutes after smoking the drug or 12 hours later.
The researchers concluded that there was no significant difference in creativity between the high or sober groups, which led them to theorize it is users’ perception of creativity that is distorted when they are high.