The chiropractic profession has in the past come under criticism for its use of the subluxation concept. For example, earlier this year Samuel Homola, a retired chiropractor, answered the question, "Is the Chiropractic Subluxation Theory a Threat to Public Health?" in the affirmative when he had a paper published under that very title in a scientific journal. [1].

I certainly agree that the chiropractic profession needs to do a lot of work in better operationally defining what we mean when we use terms like subluxation, health and adjustment. However, it smells of extreme bias when an author judges the concepts underpinning one profession harshly whilst failing to apply the same yardstick to other health care professions.

If Homola had taken the time to step back and look at the concepts that underpin the activities of other professions, for example medicine and the disease concept, he may have refrained from making the accusation that chiropractic, when built on the subluxation concept, is a risk to public health.

Let's reflect upon the medical model for a moment.

In attempting to articulate exactly what constitutes the "medical model," some general characteristics come to mind. These characteristics include unequivocal subscription to the disease model, a paternalistic hierarchy of providers, narrowly defined treatment parameters, nosological obsessions and nomothetic paradigms. [2]

Since it is fundamental to the medical model lets take a closer look at the concept of disease. Below I discuss the results of a couple of surveys that expose the very blurred line between what is, and what is not, a disease.

The first survey worth thinking about was published in the British Medical Journal (BMJ) in 1979. [3] Non-medical academics, medical academics, general practitioners, and secondary school students were invited to say whether 38 terms did or did not refer to a disease.

Almost 100% thought that malaria and tuberculosis were diseases, but less than 20% thought the following were diseases: lead poisoning, carbon monoxide poisoning, senility, hangover, fractured skull, heatstroke, tennis elbow, colour blindness, malnutrition, barbiturate overdose, drowning, or starvation. Note that all four groups, including the medical academics and general practitioners were split 50/50 over whether hypertension, acne vulgaris, or gall stones were diseases.

So why was there confusion over what was and what was not considered a disease by the participants in that survey?

Interestingly, the authors found that the presence of pathological change (which is how some dictionaries define disease) was not the strongest predictor of whether a set of symptoms/signs would be labeled a disease.

What was the strongest predictor was whether or not the participants thought the doctor had a role to play in resolving the problem. That is of course going to change across time and therefore, what is labeled a 'disease' will also change across time. This finding puts most dictionary definitions of disease on a very slippery slope. In fact so slippery that, at least one medical textbook, the "Oxford Textbook of Medicine," has chosen to stay away from defining a disease altogether.

The authors of the paper discussed above [3] state,

"Medical discourse has largely been conducted in terms of "diseases." But there is no general agreement on the definition of "a disease." The authors conclude their paper as follows: "....the idea of diseases as causes of illness, implicit in colloquial usage, must be rejected as misleading."

The second paper worth looking at [4] is again from the BMJ but this time it's a little more recent -- 13th April, 2002. The survey was conducted by the BMJ and asked its readers to identify the "top 10 non-diseases." Richard Smith, BMJ editor, claimed that the primary aim of running the survey was to illustrate the slipperiness of the notion of disease.

He states, "We wanted to prompt a debate on what is and what is not a disease and draw attention to the increasing tendency to classify people's problems as diseases."

The following points summarize the survey's findings:

*** The BMJ conducted a survey on the web to identify "non-diseases" -- and found almost 200.

*** The notion of "disease" is a slippery one and the concept of non-disease is therefore similarly blurred.

*** Health is equally impossible to define.

*** To have your condition labeled as a disease may bring considerable benefit -- both material (financial) and emotional.

*** However, the diagnosis of a disease may also create problems -- you may be denied insurance, a mortgage, and employment.

*** A diagnosis may also lead you to regard yourself as forever flawed and unable to "rise above" your problem.

The editor of BMJ concludes, "Surely, everything is to be gained and nothing lost by raising consciousness about the slipperiness of the concept of disease."

What about if we decide to take the evidence-based option as offered up by the proponents of Clinical Epidemiology. Here we might define disease as a departure from "normal." Sackett, Tugwell, Haines and Guyatt offer six definitions of normal in their book "Clinical Epidemiology," "the bible of evidence-based medicine." [5]

They suggest that if you lie more than two standard deviations from the mean on whatever measure is used (height, weight, haemoglobin concentration, and tens of thousands of others), by definition, you are diseased. By definition, 5% of people are thus "abnormal" (and therefore diseased) on each test.

You then only have to do enough tests and it doesn't take long before we are all abnormal (and therefore, by definition, diseased).

In conclusion, I suggest that although the concept of subluxation still rests on a slippery slope it is not alone and shares that slope with the disease concept that forms the very foundation of modern medicine. As Professor J.C. Keating has stated, "... the metaphor of disease has its uses and its limitations". [6]

The extent to which we as a profession are ultimately able to provide humanity with an alternative way to conceptualise health and its absence will depend in no small way on practicing chiropractors continuing to make use of our unique metaphors and concepts, and upon the direction in which we collectively focus our research time, efforts and funding. A prominent chiropractic researcher recently stated,

"These three concepts (subluxation, adjustment, health), and their interlocking relationships provide an umbrella for a chiropractic research agenda, and pose a significant challenge for the profession. If pursued properly, many controversies and questions in the clinical practice of chiropractic can be answered, given sufficient resources and time." [7]

Conflict of Interest: The author contends that he is not anti-medical, just pro-chiropractic.

1. Homolu S., "Is the Chiropractic Subluxation Theory a Threat to Public Health?" Scientific Review of Alternative Medicine. Volume 5, Number 1. Winter 2001. http://pediatrics.medscape.com/prometheus/SRAM/public/archive/2001/toc-050.html

2. McCready KF. "The medical metaphor: A better model?" 1986. http://www.heall.com/healingnews/dec/medical_model.html

3. Campbell EJM, Scadding JG, Roberts RS. "The concept of disease." BMJ 1979; ii: 757-762.

4. Smith R. "In search of 'non-disease.'" BMJ 2002; 324:883-5.

5. Sackett DL, Haynes RB, Guyatt GH, Tugwell P. "Clinical epidemiology: a basic science for clinical medicine." Boston: Little, Brown: 1991:59.

6. Keating JC. "Philosophy of the Science of Chiropractic - a primer for clinicians." FCR, CA, 1992. pp. 32-2.

7. Meeker W. "Concepts germane to an evidence-based application of chiropractic theory." Topics Clin Chiropr 2000; 7:1.