You might want to give that joint a second thought.

Recreational cannabis is legal in 24 US states, with advocates hailing the shift as a cultural victory.

But new research suggests the monumental move may come with an unexpected health concern that scientists are only beginning to uncover.

The health risks of cannabis are well-documented.

Short-term effects can include anxiety, impaired memory and dry mouth, while longer-term use has been tied to lung and blood vessel damage and even scromiting, an on-the-rise disorder that can lead to life-threatening neurological complications.

Now, a first-of-its-kind study published Thursday in BMJ Open linked recreational cannabis legalization in the US to a rise in hospital admissions for several cardiovascular diseases.

Researchers analyzed more than 50 million hospital discharge records from 2012 to 2018.

They found that admissions for atrial fibrillation (abnormal heart rhythm), heart failure and heart attacks increased faster after recreational cannabis laws took effect in the Western US than in regions without similar legislation.

Patients hospitalized for these conditions had an average age of 51, compared with 55 in other regions. They were also more likely to live in higher-income ZIP codes (26% versus 19%) and less likely to identify as white.

Before legalization, hospital discharge rates for the conditions studied were lower in the Western region than in regions without recreational cannabis laws.

But after enactment, those rates climbed faster — just over 2% faster for atrial fibrillation, nearly 4% faster for heart failure and just over 3% faster for heart attacks.

“While several studies have examined the association of recreational cannabis legalisation on psychiatric conditions, substance use, emergency visits and traffic accidents, ours is the first study to examine the association with [cardiovascular] hospitalizations,” said researchers.

Following the dank data

Cannabis may affect cardiovascular health through several physiological mechanisms, including increases in heart rate, fluctuations in blood pressure, blood clot formation and chest pain.

Legalization has also been associated with more widespread cannabis use, particularly among older adults, who already face a heightened risk of cardiovascular problems.

Because the Western region of the US started legalizing recreational cannabis back in 2014 — years ahead of other regions — researchers analyzed records across 13 Western states: Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming.

By 2018, over 98% of people in this region lived in or bordered a state with legal cannabis sales, making it the perfect case study to track how the policy shift impacted public health.

Researchers specifically monitored hospitalization rates for acute heart failure, heart attack, atrial fibrillation/flutter, ischemic (blood clot) stroke, venous thromboembolism or VTE (deep vein blood clot) and ventricular tachycardia (fast heartbeat).

To measure the impact, the team established a baseline from the two years leading up to legalization and compared Western hospitalization trends against regions where recreational cannabis remained illegal.

Researchers cautioned that this is an observational study with various limitations, like the inability to examine trends state by state, distinguish between specific methods of cannabis use or account for trends in illegal use.

Therefore, the study cannot establish that legalization directly caused the increase in hospitalizations.

“While an observational study cannot prove causality, our findings point to potential adverse effects
of recreation legalisation on population health,” said the researchers.

“Globally, our findings support a cautious approach to legalization laws accompanied by data collection on [cardiovascular] outcomes.”