The US Food and Drug Administration has a standard for determining the efficacy of new hypertension drugs: it requires “a blinded design with a placebo-subtracted reduction in diastolic BP of 5 mm Hg or more and be free of serious side effects to be approvable.”
With that guideline as their standard, a group of researchers from the University of Chicago set out to determine if chiropractic adjustment of the atlas could reduce blood pressure in patients with hypertension. The authors summarize the relationship between the first cervical vertebra (C1) and hypertension:
“Unlike other vertebrae, which interlock one to the next, the Atlas relies solely upon soft-tissue (muscles and ligaments) to maintain alignment; therefore, the placement of C-1 is pain free and thus, remains undiagnosed and untreated, whereas health-related consequences are attributed to other aetiologies.”
The position of the atlas can have an affect on the functioning of the brainstem, and, as shown in this study, can affect blood pressure. Chiropractic manipulation can adjust the position of the spine, relieving the pressure on the spinal cord.
“Minor misalignment of the Atlas vertebra can potentially injure, impair, compress and/or compromise brainstem neural pathways. The relationship between hypertension and presence of circulatory abnormalities in the area around the Atlas vertebra and posterior fossa of the brain has been known for more than 40 years.”
In this study, the researchers took 50 patients with Stage 1 hypertension who had either never been on hypertensive drugs or who had stopped taking hypertensive drugs for at least two weeks.
All of the patients were evaluated by a chiropractor for misalignment of C1 using radiographs and leg-length checks. Half of the patients received spinal manipulation of the C1; the other half received a sham treatment that was indistinguishable from a real treatment by the patient.
The diagnostic procedure was conducted at intake, after the treatment and at eight weeks.
The authors found that the patients who received the chiropractic treatment experienced a dramatic drop in average blood pressure compared to the control subjects:
The drop in blood pressure was so impressive the authors state that it “is similar to that seen by giving two different antihypertensive agents simultaneously.”
Furthermore, 85% of the patients needed only one treatment to realize the improvement in blood pressure.
In addition, the study also documented the degree of pelvic misalignment and the position of the C7 vertebra; these measurements are used with this particular method of chiropractic to diagnose dysfunction of the C1 vertebra. Just as they found with the results for blood pressure, the degree of misalignment was reduced dramatically in the treatment group, but not the control group.
“As discussed in the Methods section of this paper, techniques are now available to screen for atlas misalignment. This type of screening should be the responsibility of the primary care physician and should be performed on patients who have a history of head and neck trauma even if it is deemed insignificant. Those patients who present with pain related to head and neck trauma should not be screened. At a time when the prevalence of hypertension is increasing and its control more difficult due to a variety of factors, linking the correction of C1 misalignment to the subsequent lowering of BP may represent an important advancement in the screening of such patients.”
Bakris G, Dickholtz M, Meyer PM, Kravitz G, et al. Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients: a pilot study. Journal of Human Hypertension 2007;21:347-352.