May 2001

From World Chiropractic Alliance

No basis found for conlusion that chiropractic is linked to strokes

The implication that chiropractic care is linked to stroke is totally unsupported by clinical research, according to a leading chiropractic organization.

The World Chiropractic Alliance (WCA), responding to a paper in the May 2001 issue of Stroke, emphasized that chiropractic is among the safest of all health care disciplines. "The Stroke article was so littered with erroneous assumptions and speculation that it has no scientific value," stated Terry A. Rondberg, D.C., WCA president. The article concluded that, in people under age 45, cervical manipulations may increase -- by as much as fivefold -- the risk of a rare type of stroke called a vertebrobasilar accident.

To reach that conclusion, the researchers looked at 582 people admitted to hospitals with vertebrobasilar stroke, and found that "only 9 had a cervical manipulation within 1 week of their VBA."

However, in an interview with WebMD contributor Jeanie Davis, they admitted, ""We don't actually know that spinal manipulation was performed during the chiropractic visit. It's quite possible to go in with a neck complaint and not have a manipulation done. Some patients go to a chiropractor without a neck complaint and have a neck manipulation done... we can only infer based on the timing of events," stated lead author Deanna M. Rothwell, MSc."

According to researcher Christopher Kent, D.C., president of the Council on Chiropractic Practice, "The fact that a temporal relationship exists between two events does not mean that one caused the other. After evaluating the available literature, an expert panel found no competent evidence that specific chiropractic adjustments cause strokes."

The study's researchers also admitted they based their conclusions on assumptions and estimates. "This study design does not permit us to estimate the number of cases that are truly the result of trauma sustained during manipulation," they wrote. "Positive validation of the type of stroke would require diagnostic imaging and invasive testing well beyond the scope of the current study," they conceded elsewhere in the paper.

In addition, the study noted that cervical manipulation are performed by medical practitioners, osteopaths, and physiotherapists, as well as doctors of chiropractic. According to Dr. Rondberg, chiropractors are the only providers trained in the use of the adjustment, the specific application of force to help correct nerve interference. Manipulation is the forceful passive movement of a joint beyond its active limit of motion. Since it doesn't imply the use of precision, specificity or the correction of nerve interference, it is not synonymous with chiropractic adjustment.

Numerous published scientific and medical studies have shown that the incidence of stroke associated with chiropractic care is estimated at between one and three per million adjustments -- a number so small as to be statistically insignificant.

Matthew McCoy, D.C., editor of the peer-reviewed Journal of Vertebral Subluxation Research (JVSR), also questioned the validity of the Stroke story "The vast preponderance of research clearly shows that chiropractic is safe and not associated with any adverse events. It would be unfortunate if a flawed study discouraged anyone from getting necessary chiropractic care."

Medical researchers have already admitted that chiropractic care carries far less of a stroke risk than medical treatment. "Indeed, most interventions by allopathic physicians have a higher complication rate than chiropractic interventions," said Philip Lee, M.D., a co-investigator of a research survey presented at the American Heart Association's 19th International Joint Conference on Stroke and Cerebral Circulation.

The WCA's position paper on strokes, including abstracts of numerous scientific studies, is available at its website,

The World Chiropractic Alliance is an international organization representing doctors of chiropractic and promoting the traditional, drug-free and non-invasive form of chiropractic as a means of correcting vertebral subluxations that cause nerve interference.

For information, call: World Chiropractic Alliance, 800-347-1011 or email

2950 N. Dobson Rd. Suite 1
Chandler, AZ 85224

This article comes from Science Blog. Copyright 2004

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