Evidence of Chiropractic Safety


Chiropractors are neuro-Musculoskeletal (nMSK) experts, providing care, which begins with an assessment and diagnosis to inform safe and effective treatment, and where appropriate, preventative care. Furthermore, the College of Chiropractors of Ontario (CCO), which regulates chiropractors’ scope of practice, establishes that during chiropractic assessments, a thorough assessment of the patient is conducted on the first visit before a diagnosis and treatment plan is determined and initiated.

Spinal manipulative therapy is an established form of chiropractic treatment that constitutes a controlled act under Ontario’s Regulated Health Professions Act, 1991. Similarly, it is a controlled act that physicians also have the authority to perform under the Medicine Act, 1991.

In the interest of interprofessional transparency, independent research studies refute misinformation about the correlation of chiropractic treatments, such as spinal manipulative therapy, to the risk of stroke.

Recent examples of these research studies include:

For more details about these studies, please refer to the abstracts of each below.

Research Studies

Journal of Stroke and Cerebrovascular Diseases | Volume 26, Issue 4, April 2017, Pages 842-850
June 30, 2016, Revised September 7, 2016, Accepted October 23, 2016, Available online November 21, 2016,
Version of Record March 17, 2017.


Chiropractic manipulation is a popular treatment for neck pain and headache, but may increase the risk of cervical artery dissection and stroke. Patients with carotid artery dissection can present with neck pain and/or headache before experiencing a stroke. These are common symptoms seen by both chiropractors and primary care physicians (PCPs). We aimed to assess the risk of carotid artery stroke after chiropractic care by comparing association between chiropractic and PCP visits and subsequent stroke.


A population-based, case-crossover study was undertaken in Ontario, Canada. All incident cases of carotid artery stroke admitted to hospitals over a 9-year period were identified. Cases served as their own controls. Exposures to chiropractic and PCP services were determined from health billing records.


We compared 15,523 cases to 62,092 control periods using exposure windows of 1, 3, 7, and 14 days prior to the stroke. Positive associations were found for both chiropractic and PCP visits and subsequent stroke in patients less than 45 years of age. These associations tended to increase when analyses were limited to visits for neck pain and headache-related diagnoses. There was no significant difference between chiropractic and PCP risk estimates. We found no association between chiropractic visits and stroke in those 45 years of age or older.


We found no excess risk of carotid artery stroke after chiropractic care. Associations between chiropractic and PCP visits and stroke were similar and likely due to patients with early dissection-related symptoms seeking care prior to developing their strokes.

PMCID: PMC4470078 | PMID: 26085925
Published online Jun 16, 2015.


There is controversy surrounding the risk of manipulation, which is often used by chiropractors, with respect to its association with vertebrobasilar artery system (VBA) stroke. The objective of this study was to compare the associations between chiropractic care and VBA stroke with recent primary care physician (PCP) care and VBA stroke.


The study design was a case-control study of commercially insured and Medicare Advantage (MA) health plan members in the U.S. population between January 1, 2011 and December 31, 2013. Administrative data were used to identify exposures to chiropractic and PCP care. Separate analyses using conditional logistic regression were conducted for the commercially insured and the MA populations. The analysis of the commercial population was further stratified by age (<45 years; ≥45 years). Odds ratios were calculated to measure associations for different hazard periods. A secondary descriptive analysis was conducted to determine the relevance of using chiropractic visits as a proxy for exposure to manipulative treatment.


There were a total of 1,829 VBA stroke cases (1,159 – commercial; 670 – MA). The findings showed no significant association between chiropractic visits and VBA stroke for either population or for samples stratified by age. In both commercial and MA populations, there was a significant association between PCP visits and VBA stroke incidence regardless of length of hazard period. The results were similar for age-stratified samples. The findings of the secondary analysis showed that chiropractic visits did not report the inclusion of manipulation in almost one third of stroke cases in the commercial population and in only 1 of 2 cases of the MA cohort.


We found no significant association between exposure to chiropractic care and the risk of VBA stroke. We conclude that manipulation is an unlikely cause of VBA stroke. The positive association between PCP visits and VBA stroke is most likely due to patient decisions to seek care for the symptoms (headache and neck pain) of arterial dissection. We further conclude that using chiropractic visits as a measure of exposure to manipulation may result in unreliable estimates of the strength of association with the occurrence of VBA stroke.

RSS Education

From RSS Education – Evidence-Informed Research

The following references also refute misinformation about the correlation of chiropractic treatments, such as spinal manipulative therapy, to the risk of stroke, and are accessible to individuals with an RSS Education subscription: