Musings of a Dinosaur

A Family Doctor in solo private practice; I may be going the way of the dinosaur, but I'm not dead yet.

Tuesday, February 19, 2008

Shifting Definitions: The Diabetes "Epidemic"

Bodies don't change.

Human physiology is essentially the same now as it was twenty years ago; a hundred years ago; a thousand years ago. What has changed, of course, is our environment (in terms of sanitation, diet, activities, etc.) and our understanding of that physiology, which includes our ability to affect it through our technology, drugs and so on. Of course there are new microbes that have evolved in our environment (HIV, SARS, various other multiply resistant bacteria, etc.) but while they may tax our bodies' abilities to deal with them, those bodies don't really change.

Frequent mention has been made of the "epidemic" of diabetes, usually attributed to an increased incidence of obesity, which in turn is attributed to a higher consumption of processed foods and a decrease in exercise. These things may well be true, but there's something else that has changed just over the years I've been in practice that undoubtedly accounts for a certain percentage of the increased "incidence" of diabetes: the increased understanding of disordered glucose metabolism (and the associated role of dyslipidemia) and accelerated atherosclerosis.

Back when I was in medical school, the cut-off for an abnormal fasting blood sugar was 140. Today it's 100. We measured cholesterol, but there wasn't much we could do about it, so we didn't pay much attention unless it got over 300. We didn't even have glycosylated hemoglobin measurements; in fact, fingerstick machines for home use were just being developed. Over the years I have seen a "normal" fasting blood sugar (roughly defined by the "normal ranges" on the lab reports) drop; first from 140 to 125, then to 115, then 110, and now 99.

In retrospect, how many patients in years gone by were reassured by us that they didn't have diabetes, when by today's criteria they would indeed be diagnosed as such? Because I don't really believe that human metabolism has changed radically in only the twenty-some years since I've been in the medical field, I believe that a great many people considered to be in perfect health by the definitions of the times were in fact what we would now consider at fairly high risk for cardiac events. Along with the greater prevalence of smoking in decades past, I think this accounts for the phenomenon of "perfectly healthy" 50-somethings dropping dead of "coronaries" back in the 1960's and even into the 1970's. Although the criteria at the time said that they weren't diabetic, I think many of them probably were, at least by our current understanding of the disease.

What does that mean for patients today? Just as the "epidemic" of autism is recognized to be in large part a function of expanded definition (and perhaps greater recognition) of the condition, I believe that a greater number of people are being recognized as having the syndrome of insulin resistance -- which can progress to diabetes in the setting of carbohydrate overload and chronic couchpotato-hood -- thus artificially inflating the numbers of "people in this country with diabetes."

I don't mean to minimize the roles of a Mickey D on every corner and an SUV in every garage. Certainly a higher percentage of the population carrying the insulin resistance gene go on to express it in terms of glucose intolerance and frank diabetes when they pig out on carbs and never walk farther than the refrigerator than in decades of yore. But I am convinced that the expanded definition of diabetes in recent years contributes a hefty chunk to this "epidemic."


At Tue Feb 19, 06:09:00 AM, Blogger MedStudentGod (MSG) said...

I think it folly for anyone to assume that we are at the zenith of medical knowledge or practice. We are always seeing adjustments to guidelines, changes in optimal drug regimens, etc. Similar to hypertensives being diagnosed with ever increasingly lower BP targets, BS measurements continue to get lower and lower. Good post.

At Tue Feb 19, 08:31:00 AM, Blogger Cheryll said...

Isn't marketing wonderful? Really expands our horizons :D

Both my grandfathers dropped dead before reaching 50, but never had TV, a Big Mac, or even talkies. All the women, however, lasted into their late 80s and 90s, still active and in full possession of their (crotchety) faculties.

Being female, I'm hoping for same...Already have 'crotchety' down pat!

Perhaps 'crotchets' will become the newest epidemic, seeing as so much of the population will reach that age in the next few years...

At Tue Feb 19, 04:36:00 PM, Blogger Unknown said...

Although I generally agree with what you say, I'm not so much sure that physiology hasn't changed fairly significantly over *some* timespans. One example would be adult lactose tolerance, which looks like it's only been around for a few thousand years. There's a lack of evolutionary pressure against things we can deal with. C-sections and asthma come immediately to mind, and I'm sure there are hundreds of other things, but I suspect that improvements in health care have created a slight change in average physiology over a century or so. Over 20 years, yeah, there probably haven't been many changes in physiology, but there have been, as you say, environmental changes. Really, a huge number of environmental changes...

At Thu Feb 21, 12:55:00 PM, Anonymous Anonymous said...

There is a kid next door who was diagnosed as being on the autism spectrum. Two of their children in fact, but the one I'm thinking of is somewhat more severe than the other.

They were not diagnosed until a crisis put the family in counseling. But 20 years ago, they wouldn't have had any diagnosis but "a bit of an odd duck".

My dad and his brother probably wouldn't have been diagnosed as having diabetes either. My dad is compliant (with my mom's nagging) and my uncle is going along the lines of "they didn't think it was diabetes a few years ago, why should I worry?"

I'm concerned that a lot of that generation, the baby boomers now becoming older, who have grown up as the numbers have changed, might have a tendancy to go "what's the big deal?"

At Tue Feb 26, 12:12:00 PM, Blogger MRasey said...

This was a very interesting post and quite insightful. I have PCOS which is like metabolic syndrome with a side of infertility 'fun'. So I'm pre-diabetic essentially.

Hopefully with the bar going lower and lower, we'll decrease the number of people with fullblown diabetes.

And you're like the millionth doc I've run across who also writes. It's gotten to where I ask docs what genre they write. You know, I think docs are the modern day renaissance men/women. Scientists and artists.



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