Burton J. Tabaac, MD
@burtontabaac
As stroke is becoming a more prevalent etiology of death for young adults 25 to 45 years old, there is naturally a growing interest focused on modifiable risk factors for stroke prevention. The focus of this publication is aimed at drug use, namely marijuana, and if it plays a role as a causative or contributing factor to ischemic stroke. There is well documentation in the literature to support tobacco smoking and cocaine use as risk factors for stroke, yet a causal relationship for marijuana remains less clear. This article grows even more prescient given the rapidly growing rise of marijuana use in the United States, especially amongst 18- to 25-year-olds.1
To date, there exist few epidemiological studies to evaluate the association between marijuana use and acute ischemic stroke, with some reports suggesting conflicting findings indicating no association with stroke risk; the potential for a dose response effect has been postulated. As more states and local governments pursue the decriminalization and legalization of marijuana, further clarification to delineate the potential risk of stroke becomes ever more paramount to public health interest. The authors of this paper investigated a large population-based case control study of ischemic stroke in young adults to assess whether self-reported marijuana use was associated with early-onset ischemic stroke, and evaluated for a dose-response temporal relationship.
The researchers amassed a total of 1090 cases (patients diagnosed with a first-ever ischemic stroke aged 15 to 49 years) and 1152 controls from 59 hospitals, then excluded any patient that reported a history of vasoactive drugs known to increase stroke risk, e.g., cocaine or amphetamine derivatives such as MDMA. The resultant final study population consisted of 751 cases and 813 controls. Interestingly, the authors illustrate a comparison between ever versus never users of marijuana, highlighting that among controls, ever use of marijuana was more often reported among men than women and more among White subjects than Black subjects. Marijuana users were more likely to be current cigarette smokers and users of alcohol. There were similar rates of ever marijuana use among the stroke patients and their peers in the control group, with ever use of marijuana not revealing an association with stroke after adjusting for age, sex, race, the amount of current smoking, current alcohol use, hypertension, nor diabetes.
The SPYA (Stroke Prevention in Young Adults Study) did not demonstrate a statistically significant association between marijuana use and ischemic stroke in young adults. The study also did not reveal a temporal link between self-reported marijuana use and ischemic stroke. A limit of the SPYA is that there were very few weekly or daily marijuana uses identified in the study population, thus limiting the statistical power to assess risk in these groups. As it pertains to cocaine use, a similar analysis did successfully show a strong temporal relationship to acute ischemic stroke.
This is the largest case-control study to date of its kind. As this study focused on acute ischemic stroke, there remains the question of whether marijuana use is a possible risk factor for intracerebral and/or subarachnoid hemorrhage. It may be revealing and relevant to detail the route in which the patients imbibed marijuana, underscoring that smoking and combustion carries with it separate risk that edibles and consumption via oral route may necessarily not. Additionally, as the patients were recruited from 59 hospitals in the Baltimore-Washington region, one would be keen to acknowledge the concomitant prevalence of synthetic cannabinoids in this region, which has been well documented in the literature to be associated with cerebrovascular insults and disease.2 Further research focused on heavy marijuana use, to increase statistical power, would minimize limitations to better assess if high frequency or high dose use is associated with increased ischemic stroke risk.
When the senior author of the study was reached for comment, Dr. John W. Cole shared, “While our study did not demonstrate marijuana to be a strong risk factor for ischemic stroke, regular use may be detrimental akin to regularly smoking cigarettes, hence both should be avoided.”
References:
- Jacob, Julie A. “Marijuana use has doubled among US Adults.” Jama 314.24 (2015): 2607-2607.
- Bahouth, Mona N., et al. “Synthetic cannabinoid-associated coagulopathy secondary to long-acting anticoagulant rodenticides: Observational case series and management recommendations.” Medicine 98.36 (2019).
