Findings in a new study indicate that marijuana use alone doesn’t increase the risk of stroke.
Marijuana use alone doesn’t increase the risk of stroke in adults younger than 60 years old, according to a new study from an international team of researchers from Sweden and France.
The population-based cohort study, published online December 27 in the American Heart Association journal Stroke, examined the relationship between stroke risk and marijuana use in 49,321 Swedish men born between 1949 and 1951 and drafted into military service at ages 18 to 20.
Participants filled out two detailed questionnaires – one focused on substance use and the other on social and behavioral factors. The researchers, headed by Daniel Falkstedt, PhD, obtained information on any stroke events that occurred in the participants up to the age of 60 from national databases, including any strokes experienced before the age of 45.
“[B]y examining cannabis use in young adulthood in relation to subsequent risk of stroke in a large population-based cohort, we found no evident association between cannabis use and stroke, including stroke before 45 years of age,” the study concluded. “Tobacco smoking, however, showed a clear, dose-response shaped association with stroke.”
The leading cause of serious, long-term disability in the United States, strokes occur in approximately 795,000 people every year. A stroke occurs when blood flow to the brain is interrupted or markedly limited, subsequently depriving the brain cells of the oxygen and nutrients necessary for survival. Because of the loss of brain cells, strokes can cause temporary and permanent disability.
Risk factors for stroke include heavy drinking, the use of cocaine and methamphetamines, obesity, and cigarette smoking. In the study, stroke use was shown to be higher in those that used cannabis, but when risk was weakened once the researchers adjusted for tobacco use.
“The almost doubled risk of ischemic stroke following heavy cannabis use that was observed in our study disappeared when we controlled for tobacco smoking,” study author Dr. Anna-Karin Danielsson of Karolinska Institutet in Stockholm told Reuters Health via email.
Smoking more than 20 cigarettes per day was found to be clearly associated with an increased risk of strokes.
“Extensive tobacco smokers in late adolescence had a fivefold increased risk of stroke before age 45, when compared to non-smokers, and more than double the risk of stroke (up through) age 60,” said Danielsson.
The men who suffered a stroke were also found to more likely be overweight, have low cardiorespiratory fitness, drink higher amounts of alcohol, and have a low socioeconomic position in childhood.
Findings in previous studies indicate that administering the cannabinoids found in cannabis shortly following a stroke can protect from permanent disability by limiting brain cell damage. Both animal and human studies have found cannabinoids to improve functional outcome following strokes. One study also found cannabis to be beneficial in helping people quit smoking cigarettes.
You can access the entire study, “Cannabis, Tobacco, Alcohol Use, and the Risk of Early Stroke,” on the Stroke journal website.
Learn more about what studies have shown on cannabis’ therapeutic benefits for recovering from a stroke by visiting our education page.