Chiropractic Cuts Blood Pressure

The above headline comes from a March 16, 2007 article on WebMD. The article is based on a study done at the Hypertension centre at the University of Chicago Medical centre and published in the March 2, 2007 issue of the Journal of Human Hypertension.

In this study, 50 patients with hypertension were divided into two groups of 25 each. One group of 25 received a specific light force chiropractic adjustment (administered by a chiropractor) to the Atlas vertebrae (uppermost bone in the neck). The other group of 25 received a similar procedure but with no adjustment being given. Researchers called this procedure the “sham adjustment”. Since the type of adjustment given was very light force, the patients involved in this study did not know if they were receiving the real or sham adjustments.

The results were surprising to even the medical researchers conducting the study. After 8 weeks of care the 25 people in the group receiving the real chiropractic adjustments all showed a significant reduction in blood pressure compared to the group that received the sham adjustment. Those patients who got the real adjustment showed an average of 14 mm Hg greater drop in systolic blood pressure (the top number in a blood pressure count), and an average of 8 mm Hg greater drop in diastolic blood pressure (the bottom blood pressure number) over those who got the fake or sham adjustment.

In his interview with WebMD, study leader George Bakris, MD commented, “This procedure has the effect of not one, but two blood-pressure medications given in combination. And it seems to be adverse-event free. We saw no side effects and no problems.”

When they first analyzed the data, Dr. Bakris and his statistician had trouble believing the data. He noted, “When the statistician brought me the data, I actually didn’t believe it. It was way too good to be true. The statistician said, ‘I don’t even believe it.’ But we checked for everything, and there it was.”

X-rays were used to confirm that the chiropractic adjustments actually changed the position of the Atlas vertebrae. Dr. Marshall Dickholtz was the chiropractor who performed the specific adjustments and commented in WebMD, “At the base of the brain are two centres that control all the muscles of the body. If you pinch the base of the brain — if the Atlas gets locked in a position as little as a half a millimeter out of line — it doesn’t cause any pain but it upsets these centres.”

Even with the overwhelming results, the authors of the study were cautious in their conclusions and posed several questions. They commented, “The mechanism as to why this improvement in blood pressure occurs is unknown and cannot be determined by this study”. They continued, “The data presented, however, raise a number of important questions including: a) How does misalignment of C1 affect hypertension?; and b) If there is a cause and effect relationship between C1 misalignment and hypertension, is malposition of C1 an additional risk factor for the development of hypertension?”