Smoking Cannabis May Double the Risk of Stroke

It's not just tobacco smoke that harms the vascular system, it seems. From the International Stroke Conference in Honolulu. Here's the discussion in Medscape since the stroke conference website is down today.

Honolulu, Hawaii — More evidence that smoking cannabis is associated with an increased risk for stroke has come from a New Zealand study.

The first case-control study to investigate this association, presented at the American Stroke Association's International Stroke Conference (ISC) 2013, found that patients with ischemic stroke/transient ischemic attack (TIA) were twice as likely to have recently used cannabis as age-, sex-, and ethnicity-matched controls.

"Cannabis is generally perceived as having few serious adverse effects, but this study suggests that this may not be the case," lead author Alan Barber, PhD, MD, from University of Auckland, New Zealand, concluded.

For the study, Dr. Barber and colleagues tested urine for cannabis within 72 hours of hospital admission in 160 patients with ischemic stroke/TIA aged 18 to 55 years and 160 controls (patients admitted with nonstroke diagnoses, matched for age, sex, and ethnicity).

The cannabis screen was positive in 25 (16%) of the stroke/TIA group vs 13 of 160 (8%) control participants. Logistic regression analysis found an odds ratio of 2.30 (95% confidence interval, 1.07 - 4.95).

Dr. Barber said the 16% rate of cannabis use in the stroke patients "took us by surprise." Cannabis users were more likely to be male, tobacco smokers, and Maori. No other illicit drugs were detected.