Cannabis, Ischemic Stroke, and Transient Ischemic Attack
A Case-Control Study
Peter Alan Barber, PhD, FRACP, Heidi M. Pridmore, FRACP, Venkatesh Krishnamurthy, FRACP, Sally Roberts, FRACP, FRCPA, David A. Spriggs, FRACP, Kristie N. Carter, PhD and Neil E. Anderson, FRACP
+ Author Affiliations
From the Departments of Neurology (P.A.B., H.M.P., V.K., N.E.A.), Microbiology-LabPlus (S.R.), and General Medicine (D.A.S.), Auckland City Hospital, Auckland, New Zealand; and Department of Public Health, University of Otago, Wellington, New Zealand (K.N.C.).
Correspondence to P. Alan Barber, PhD, FRACP, Auckland City Hospital, Park Rd, Grafton, Auckland 1001, New Zealand. E-mail firstname.lastname@example.org
Background and Purpose—There is a temporal relationship between cannabis use and stroke in case series and population-based studies.
Methods—Consecutive stroke patients, aged 18 to 55 years, who had urine screens for cannabis were compared with a cohort of control patients admitted to hospital without cardiovascular or neurological diagnoses.
Results—One hundred sixty of 218 (73%) ischemic stroke/transient ischemic attack patients had urine drug screens (100 men; mean [SD] age, 44.8 [8.7] years). Twenty-five (15.6%) patients had positive cannabis drug screens. These patients were more likely to be men (84% versus 59%; χ2: P=0.016) and tobacco smokers (88% versus 28%; χ2: P<0.001). Control urine samples were obtained from 160 patients matched for age, sex, and ethnicity. Thirteen (8.1%) control participants tested positive for cannabis. In a logistic regression analysis adjusted for age, sex, and ethnicity, cannabis use was associated with increased risk of ischemic stroke/transient ischemic attack (odds ratio, 2.30; 95% confidence interval, 1.08–5.08). However after adjusting for tobacco use, an association independent of tobacco could not be confirmed (odds ratio, 1.59; 95% confidence interval, 0.71–3.70).
Conclusions—This study provides evidence of an association between a cannabis lifestyle that includes tobacco and ischemic stroke. Further research is required to clarify whether there is an association between cannabis and stroke independent of tobacco.