STATS Spotlight

The Dangers in Chiropractic

by Howard Fienberg
February 2002

Given all the lifting, stretching we do every day, it sounds nice to have someone who can alleviate the pain in our necks or work the kinks out of our backs. That may be what makes chiropractic so popular. Is this such a bad thing? After all, where is the harm? A lot of people swear by chiropractors; if people think it works for them, whom are we to judge?

Contrary to popular perceptions, chiropractic may present serious health risks. Previous research hinted at a link between chiropractic and stroke. Now, there is a new study providing more solid evidence that chiropractic treatment increases the risk of stroke.

So what is chiropractic anyhow? Chiropractors manipulate the spine in order to correct spinal “subluxations.” This manipulation is purported to fix medical problems ranging from mundane back pain to major diseases. Subluxations are supposedly troubles in the spine which interfere with the function of the nervous system – what chiropractic’s inventor Daniel D. Palmer called the “Innate Life Force.” Palmer had been trying to explain why germs were found in both healthy and sick people. His answer was subluxation, which he believed to be the root of all disease. Soon thereafter, modern medicine realized that the real secret was the immune system. Most chiropractors, while unable to agree on a precise definition of subluxation, have yet to acknowledge this simple scientific discovery.

According to Dr. William T. Jarvis, professor of public health at Loma Linda University, no “chiropractor has ever been able to reliably demonstrate the existence of ‘subluxations,’ much less validate their importance to health and disease.” Dr. Jarvis does admit that “there is sufficient evidence that manipulation can at least temporarily improve the range of motion of impaired joints and relieve pain ... to make it a worthwhile, although limited medical procedure.” But the most likely reason for chiropractic’s popularity lies in the “laying on of hands, which reportedly has the effect of relaxing the patient.”

A good measure of a treatment’s usefulness comes from replication. Can chiropractors reliably diagnose subluxations? Reporter Ralph Lee Smith discussed in his 1969 book, At Your Own Risk, his trips to two different chiropractors, from whom he received completely different subluxation diagnoses. Similar trials have been run since then, including those by consumer advocate Dr. Stephen Barrett, who sent a healthy four-year-old girl to five chiropractors for a simple check-up. Each found something entirely differently wrong with her, ranging from a “twisted” pelvis, to an “elevated” hip, to a “shorter left leg.”

So chiropractic is not exactly a reliable medical treatment. But might it be dangerous? A recent study from the Canadian Stroke Consortium concluded that it seems to be so. Using data from a Canadian stroke registry, the researchers found 98 cases where external trauma was fingered as the culprit in ischemic strokes (strokes caused by the formation of blood clots in arteries which would otherwise supply the brain with blood). Chiropractic-style neck manipulation apparently caused 38 of those cases.

Neurologists think chiropractors can damage the vertebral artery, which rises to the stem of the brain in two right-angle turns, by twisting the neck beyond its natural limits, tearing the artery in a sudden, jerky motion. The researchers concluded that there may be a “gross underreporting” of chiropractic manipulation as a cause of stroke.

The data is incomplete and this is still preliminary work. Because of these limitations, estimates of the risk of stroke range from 1 in 5,000 to 1 in a million. Further research may show chiropractic to be relatively safe, but the data so far do not support that conclusion.

Chiropractors usually rely on anecdotes to defend their practices. Supporting scientific evidence is lacking, and most scientific studies that have been advanced in support of the practice are not up to scratch. The bitter truth, for real doctors and for alternative medical practitioners, is that most ill people improve on their own. Their ailments are usually poorly defined, rarely fatal and don’t usually degrade in a straight and simple pattern. While medicines and methods might appear to be effective, discerning their real effect is difficult. That is why we have scientific research – so that we can tell the difference between medicine and quackery.

What can we learn from this most recent study? Indices of popularity cannot substitute for scientific evidence. We do not know if chiropractic is anything positive for our health and negative indicators are growing.

Most of all, we can no longer simply shrug our shoulders and ask, “What’s the harm?”

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