What is Disease?

This may sound like a silly question, everyone knowswhich is believed to place someone at increased risk
what disease is. But have we ever bothered tofor a disease. These risk factors may either be
define disease, or health for that matter. Right now,something which can't be changed, such as family
in the United States, there is an enormous politicalhistory, gender, or presence of a particular gene, or
debate about "health care delivery" which is, at leastones which can be changed such as the habit of
ostensibly, about improving the health of the citizens.smoking or having high blood pressure.
Is "health" though a commodity which can beThese second type of risk factors are called
delivered by government? Throughout the world,"modifiable risk factors" and over the past half a
governments have enormous bureaucracies andcentury a tremendous amount of effort has been
departments tasked with addressing health andplaced on attempting to change "modifiable risk
disease such as the National Institutes of Health andfactors" so that disease doesn't occur in the first
the Centers for Disease Control. The US Food andplace. While this is a noble goal, it is also one that is
Drug Administration by some estimates regulatesmore "risky" than simply treating a disease for a
some one sixth of the US economy, when itnumber of reasons. You see, by any definition,
approves a drug it does so based from clinical trialssomeone who only has a risk factor for a particular
which are intended to show a drug is both safe anddisease, does not have the disease, therefore
effective against a particular disease. So again, whywhatever "medicine" you are giving is not being given
don't we start at the very beginning and ask justto treat disease it is being given to a healthy person.
what is disease? When you think about it for a whileAll medicines carry with them a certain degree of risk
you begin to realize that, like defining "life", it is not atand it is a whole different proposition to be giving
all easy to define health or disease.medicine to a healthy person than to a sick person. If
For example, what a healthy 20 year old and aone was diagnosed with an incurable cancer and was
healthy 80 year old can do are generally muchtold a drug would give them a 50% chance of a cure
different. If a twenty year old could not run a milebut would triple their risk of a heart attack or
one would worry about disease, if an eighty year oldincrease their chance of having leukemia in later life
could run a mile we would be impressed. If one has athey likely wouldn't give a second thought to taking
broken leg, while one is not healthy, I don't know ofthe drug. If one the other hand, someone was in
any culture that would call them diseased. So, it is notgood health and was told that a drug would give
simply diminishment, or even loss of function or abilitythem a 50% less chance of ever developing the
which defines disease. If the same individual however,cancer but it would triple their risk of heart attack it
had a broken leg not from falling off a ladder but asis an entirely different situation. If instead of
a consequence of cancer or a genetic condition, thenpreventing the cancer, the drug instead only prevents
we likely would speak of them as having disease.heartburn or joint pain and has no effect on risk of
How about a patient who has recovered fromor progression of disease the risk/benefit scenario is
cancer, at what point is the disease no longer "ineven further skewed away from wanting to take
remission" but instead the person is free of disease?the medicine.
What about carriers of infectious disease such asWhen you give medicine to a sick person it is
"typhoid Mary" or someone who doesn't realize theygenerally for a very limited period of time, i.e. until
have tuberculosis, do they themselves have disease?they get better. If you rely on a medicine to change
Suppose Typhoid Mary was a hermit who nevera risk factor for disease they may be on it their
interacted with others, do they have disease at thatwhole lives. This again greatly increases the possibility
point? What about someone with latent or inactiveof a serious side effect to occur from the medicine.
tuberculosis (this is some one third of the worldThe number of people with a risk factor for a
population), they have no effects from tuberculosis,disease will also be much larger than the number of
they are not contagious to others, yet, they maypeople with the actual disease. This means the
have a walled off cyst of live tuberculosis bacterianumber of people on the medicine will be very large
somewhere in their lungs.and even rare serious side effects may end up
Medical practitioners speak of the "signs" andaffecting a large number of people. Moreover, for
"symptoms" of disease. The signs of disease areany one disease, there may be multiple modifiable risk
those changes appreciable to the senses whichfactors which might be treated pharmacologically. So
indicate disease. So, for instance, a fever is a sign ofas is often the case, someone in perfect health may
disease, the crackles and wheezes heard through abe on multiple medicines to treat various risk factors
stethoscope are signs of disease. These signs offor disease.
disease are investigated in the physical exam andThis again increases the possibility of interactions
other diagnostic tests which may be ordered. Thebetween the various medicines leading to an adverse
symptoms of disease on the other hand are whatevent. Finally, it is much more difficult to study and
the patient is experiencing. So a patient may say, Idetermine with any confidence whether treating
feel chills, when the physical exam finds a fever, or Isomeone with a risk factor for disease is actually
am coughing a lot when the exam hears wheezes inimproving their long term health. For one, only a small
the lungs and the x-ray shows a picture of a fluidpercentage of the people with a risk factor for
filled lung, or a child may say that their ear hurts anddisease would be expected to develop the disease
looking at the ear with an otoscope the nurse orso the numbers involved to find any sort of possible
doctor sees an inflamed middle ear. Sometimes, thedifference between treated and untreated groups
patient will have symptoms of disease, when nomust be very large. Secondly, the studies must be
signs of disease can be found, so for instance thevery long term, over years or decades even to begin
patient says, I have a headache and after an examto get an idea of who might develop disease.
turns up nothing unusual the doctor says take twoBecause of these logistical problems there won't be a
aspirin and call me in the morning. Other times therelarge number of confirmatory studies, and as with
can be signs of disease but no symptoms, so aany other scientific study one must be concerned
patient may go for an annual physical and thoughabout the possibility of bias, especially if one is only
they feel healthy are told your blood sugar level isrelying on a small number of studies. Even if one does
very high, you may have diabetes.improve the risk for developing a disease has one
I wanted to start with this philosophical look atimproved overall health. As has often been the case
disease so as to present two arguments. First,only after a drug has been approved and been given
Western Medicine generally does a good job treatingto millions of people does it become apparent that
disease and second most of what Western Medicinethe damage outweighs any benefit.
does is not treatment of disease. The first pointTomorrow we will look more into the issue of giving
could be argued at length, I would just ask if you hadmedicine to healthy people as well as the related
a serious acute disease, say an appendicitis, whereissue of treating the symptoms of a disease without
would you want it treated? The second pointtreating the disease itself and conclude with a
requires some more discussion to be taken seriously.modest proposal for how to change the drug review
To do this we need to introduce some more medicalprocess.
terminology. A "risk factor" for a disease is something