Diseasification of Obesity

In a thoughtful, measured and well-reasoned blog post in these pages, Dr. Keith Ayoob recently discussed the AMA’s decision to classify obesity as a “disease.” As he concluded his post, Dr. Ayoob wrote: “I don’t care how obesity is categorized. I care about what’s being done about it…. We need to stop talking about whether obesity is or is not a disease and start talking about preventing it altogether.” This got me thinking: does the process of “diseasification” hold any promise at all in obesity? And are there downsides to this approach that should cause us concern?

“Diseasification” is a funny and not entirely real word, but I didn’t make it up. Sure, if you look for it in an online dictionary, you won’t find it—but if you Google it, you’ll find over 6,000 hits. Most seem to focus on one of the most problematic aspects of diseasification: that of classifying all sorts of mental states and psychological issues as diseases, a tendency that has arguably contributed to our nation’s overreliance on pharmacology to ease the vicissitudes of daily living. But some of these Google hits refer to issues in prevention, including obesity. While I didn’t coin the term, I think its meaning is self-evident: labeling as a “disease” a condition that is typically not so construed. Clearly, the AMA’s action would fit under this intuitive definition.

Of course, this begs the question: what is a “disease”? A typical definition of disease provides guidance, if not absolute clarity: “any deviation from or interruption of the normal structure or function of any body part, organ or system that is manifested by a characteristic set of symptoms and signs and whose etiology, pathology and prognosis may be known or unknown.” In holding obesity up to this standard, its appropriateness could hinge on whether a body with a body mass index (BMI) greater than 30 would be considered a “normal structure”; this in turn depends on how we define “normal.” Ironically, if we refer to a standard statistical concept of outliers—usually, the most extreme 5 percent or so of a population—then the more widespread our so-called national obesity epidemic, the more “normal” obesity becomes. Currently, more than a third of the entire U.S. population is obese; in certain states and in some ethnic/racial groups, the proportion is closer to half. Clearly, these are not “outliers.”

But I think the annals of preventive medicine have demonstrated that diseasification has its place. Let us look at a reasonably successful story of diseasification: that of hypertension. Some readers might be surprised that I’m considering this “diseasification”: after all, isn’t hypertension clearly a disease? Well, no, it’s not. There are no symptoms, illnesses or dysfunctions related to hypertension per se. Hypertension refers to an elevated blood pressure, where “elevated” was established in a discretionary (though certainly not arbitrary) manner. Coincidentally, about a third of all Americans fit the definition of people with hypertension, so these are also not “outliers” in the traditional sense. But what we do know is that high blood pressure is a major, modifiable risk factor for things that are diseases—important ones, such cardiovascular diseases, of stroke and heart attack. Moreover, we know that pharmacological efforts to lower blood pressure below established cutpoints leads to a reduction in the risk of such diseases. So diseasifying hypertension has led to helpful treatments and to a reduction in disease outcomes.

Obesity, however, is a wholly different animal. First, while obesity has been shown to be a risk factor for certain diseases—indeed, many of the same diseases predicted by high blood pressure—its association with those diseases is neither so strong nor so direct as that with hypertension. Moreover, healthcare practitioners do not have the sorts of treatments in their toolkits to treat obesity that they do for high blood pressure, and even more significantly, there is no direct evidence that using treatments to lower BMI will in turn reduce the risk of the real diseases that are associated with obesity—the ones we really care about. Thus, the presumed “upsides” of this new AMA-endorsed classification are hard to imagine. Given the lack of effective and proven therapies, what benefit do we seek? Prevention, as Dr. Ayoob indicated, is key—but our rapidly exploding national obesity prevalence isn’t caused by lack of adequate medical care; rather, it is due to wholesale changes in diet and lifestyle, largely promoted by corporate marketing, governmental policies, new technologies and changing norms of behavior. These are amenable (alas, not easily) to public health interventions and policy change, but not to increased doctor visits.

An open question is: if this relabeling of obesity has an impact on the stigmatization of the overweight, will it be for good or ill? On the good side, perhaps, is recognizing that it isn’t necessarily a sign of sloth or weakness of will, but something that may be beyond volitional control, much as classification as disease may have improved the situation for alcoholics or substance abusers. On the other side—do we really want to equate obesity with such things? I think we ought to heed lessons from the fat acceptance movement, and consider that the overweight seem to be the last social group that it is deemed acceptable to malign. Certainly, there are many fat people comfortable in their own bodies; do we really want to say to them, “Sorry, it doesn’t matter what you think, you’re sick”? Not a necessary corollary of diseasification, I think, but a cause for concern.