Back in the 1950s, Jean Vague observed that central, also called abdominal or visceral obesity (i.e., the so-called “apple”-shaped body, as distinguished from the “pear”-shaped body of noncentral or subcutaneous obesity), is more likely associated with metabolic abnormalities. But even that observation, while generally true, has been called into question. Young and Gelskey, publishing in JAMA almost 20 years ago, for example, concluded that “noncentral obesity,” even in a cross-sectional sample of almost 2800 Canadian adults, was most definitely not benign compared to the non obese, even though their metabolic profiles were not as severe as those with central obesity.
For years, researchers and clinicians, though, have also documented the existence of a subgroup (some reports as high as 1/3 of obese people), as measured by elevated body mass index (BMI), including those with abdominal obesity, who have no metabolic abnormalities. In other words, these individuals have been considered metabolically healthy, with no evidence of hypertension, abnormal lipid or glucose levels, insulin resistance (or even overt type II diabetes), as well as other markers of inflammation (e.g. increased blood levels of C-reactive protein) that are typically found in obese people.
There are those, furthermore, who believe in “health at any size” and that cardiovascular fitness, as measured by exercise on a treadmill, for example, is far more important than percentage of body fat or even BMI in terms of mortality or even morbidity. This was the conclusion of a large 2013 study, published in the European Heart Journal by Ortega et al. The study population, though, was not a typical one: they were overwhelmingly Caucasian, well-educated, held professional or executive positions and those who were obese were only in the Class I obesity range as assessed by BMI. Ortega and colleagues acknowledged that one of the problems with the concept of benign obesity is that there is no clear, generally accepted and standardized definition of metabolic health. For example, is it acceptable to have one metabolic abnormality or two (and if so, which one is the most significant) to still count as healthy? It depends on the study, and so it is even difficult to know its true prevalence among those with excessive weight.
So is there really such a thing as “healthy” or “benign” obesity” or is that an oxymoron, i.e., a contradiction in terms? A recent study, published in the Annals of Internal Medicine by Caroline K. Kramer, M.D., Ph.D. and her colleagues, calls into question the concept of healthy obesity. These researchers report on 12 studies and conducted a meta-analysis on 8 longitudinal studies that investigated mortality and/or cardiovascular events in over 61,000 normal weight, overweight, and obese adults. They found that even when obese people had no metabolic abnormalities, if followed longitudinally for at least 10 years, there is “no healthy pattern of increased weight” and these people are “at increased risk for adverse long-term outcomes.” This is not a completely new finding--for years, others have called into question the concept of metabolically benign obesity. For example, John McEvoy and his colleagues called it “a wolf in sheep’s clothing” in a 2011 article in the journal Athlerosclerosis and suggested that “nomenclature in the field of obesity should forever abstain from all use of the word “benign.” The Kramer study, though, was the first systematic review and meta-analysis that focused on long-term follow-up. If followed over time, are these really so-called “patients-in-waiting?”
The first reference I could find to the concept of “patients-in-waiting” was in a 2004 article by Parry and colleagues on the “limbo” feeling patients may experience prior to having their diagnosis of type II diabetes confirmed. Much more recently, Timmermans and Buchbinder, in their 2010 article in the Journal of Health and Social Behavior, describe “patients-in-waiting” as “an umbrella concept” for patients who, as a result of genetic screenings, may find themselves potentially living “under medical surveillance between health and disease.” In other words, these patients may learn that they have a more likely genetic predisposition to contract a disease (e.g. Alzheimer’s or breast cancer) eventually, even though they have no evidence of that specific disease at the time of the genetic screening. It was this kind of information, for example, that prompted actress Angelina Jolie, though apparently asymptomatic at the time but with a strong family history of breast cancer, to opt for a preventive bilateral mastectomy.
Bottom line: Whether benign obesity does exist, at least in a small percentage of people, may still be open to question, but these studies have significant clinical implications. Those who are overweight or obese, regardless of where their fat accumulates and regardless of being presently asymptomatic, should not be complacent and should not assume they will necessarily remain healthy, especially if their BMI increases over time. Their metabolic health may, in fact, be transient. Over time, they may likely develop the typical complications seen most commonly in those with central obesity. In other words, they should see themselves as potentially “patients-in-waiting” and consider the importance of lifestyle modifications such as exercise and diet.