On May 30, 2016, the the Annals of Vertebral Subluxation Research published a study titled, “Systematic Review and Meta-analysis of Chiropractic Care and Cervical Artery Dissection: No Evidence for Causation.” The researchers evaluated the evidence related to chiropractic manipulation and the form of stroke known as CAD. They found no causation.
On a number of occasions, chiropractors have claimed that a smear campaign was being waged on their profession by baseless claims that chiropractic could cause strokes. This study looked at the actual scientific evidence to see if there was a causal relationship shown anywhere in the scientific data.
The study points out that there have been a number of case studies of patients who had CAD strokes following a chiropractic adjustment. However, this alone does not mean that the CAD was a result of the adjustment. As an example, there were probably also a number of people who have had car accidents at some point after a chiropractic adjustment. This would not mean that the chiropractic care caused the auto accident.
The researchers looked at the raw data to see what real scientific evidence there was for the claims. As the researchers stated, “We sought to examine the strength of evidence related to this question by performing a systematic review, meta-analysis, and evaluation of the body of evidence as a whole.”
Researchers did extensive searches for any references to chiropractic care and stroke. In so doing, they found 253 articles on the subject. Of these 77 articles were non-relevant and excluded. The remaining studies were reviewed for the strength of the evidence and the methodology leading to the results. Some studies showed no relationship with chiropractic and stroke, while some studies suggested that the risk was due to the condition that the patient had prior to the chiropractic care. In these studies, the stroke risk was the same, regardless if the patient went to a chiropractor or a medical doctor.
After reviewing all available studies, the researchers concluded that there was no evidence to suggest that chiropractic caused stoke. “We found no evidence for a causal link between chiropractic care and CAD.” They further explained the impact of their findings by noting, “This is a significant finding because belief in a causal link is not uncommon, and such a belief may have significant adverse effects such as numerous episodes of litigation.”