Risk of Vertebrobasilar Stroke and Chiropractic Care
Results of a Population-Based Case-Control and Case-Crossover Study
J. David Cassidy, DC, PhD, DrMedSc,†‡ Eleanor Boyle, PhD, Pierre Coˆte ́, DC, PhD,†‡§ Yaohua He, MD, PhD, Sheilah Hogg-Johnson, PhD,†§ Frank L. Silver, MD, FRCPC,¶ and Susan J. Bondy, PhD†

Key Points
● Vertebrobasilar artery stroke is a rare event in the population.
● There is an association between vertebrobasilar artery stroke and chiropractic visits in those under 45 years of age.
● There is also an association between vertebro- basilar artery stroke and use of primary care physician visits in all age groups.
● We found no evidence of excess risk of VBA stroke associated chiropractic care.
● The increased risks of vertebrobasilar artery stroke associated with chiropractic and physician visits is likely explained by patients with vertebro- basilar dissection-related neck pain and headache consulting both chiropractors and primary care physicians before their VBA stroke.