Straight Talk: Defending the Obesity Paradox and Conflicts of Interest
Almost 15 years ago, my colleagues and I at Ochsner were doing a study to determine if peak oxygen consumption (VO2) corrected for lean weight instead of total weight was a better predictor of heart failure (HF) prognosis. We theorized that body fat did not have much perfusion or metabolism (we now know that the adipocytes, however, are an important endocrine organ), so higher body fat would artificially dilute the peak VO2 and make HF prognosis appear to be worse than it really was. In fact, our theory proved to be correct and resulted in a JACC paper in 2000.1
However, when studying this issue, we accidentally stumbled upon the fact that the HF patients who died had lower body mass index and body fat percentage than those who survived; in fact, a higher body fat percentage was a strong independent predictor of better survival, with a 13% reduction in mortality for every 1% increase in body fat. Although it was very difficult to get these data published, William C. Roberts, MD, eventually accepted the paper in the American Journal of Cardiology, which has now been cited more than 300 times.2
I must admit that what has proved to be groundbreaking research has been quite controversial and surprising to me as a physician; in many ways, the "obesity paradox has turned conventional wisdom on its head. There is no question that obesity adversely affects most of the major cardiovascular disease risk factors by increasing arterial pressure, adversely affecting lipids (especially increasing triglycerides and reducing levels of the cardioprotective HDL-cholesterol), raising glucose levels (and increasing the risk of impaired fasting glucose, metabolic syndrome, and type 2 diabetes mellitus), as well as inflammation (e.g., C-reactive protein).
Not surprisingly, most cardiovascular diseases are increased in the setting of obesity. However, although our initial studies in the early 2000s were highly criticized by reviewers as being implausible and flawed, now the obesity paradox has been demonstrated in HF, coronary heart disease, hypertension, atrial fibrillation, and many other conditions, including in individual studies and large meta-analyses. Although the exact mechanisms for this puzzling obesity paradox remains unclear and controversial, and some studies suggested that this is due to various confounders (which I disagree with for the most part), now currently many physicians recognize this paradox, particularly in patients with cardiovascular disease.
Unlike 2 decades ago, I now have even more concern for lean patients with cardiovascular disease, as opposed to the overweight/ obese patients, at least regarding long-term prognosis. I have been honored to provide several State-of-the- Art papers on this topic in the JACC journals,3-5 the first of which has been cited more than 600 times.
When I was approached to write about this topic for lay people, I was at first skeptical because I had previously only published in clinical arenas, and I was concerned that it may be perceived that I was promoting obesity or encouraging normal weight patients to gain weightwhich is far from the truth. However, my book agent convinced me that bringing this message to the public was an important one, which hopefully would allow many patients to learn that thinner is not always healthier and that, although fat has been often demonized by our society, fat is not always the "devil."
In fact, our research shows that fitness is much more important than weight regarding long-term health outcomes, which is discussed in detail in my last JACC State-of-the-Art paper5 and in my book, The Obesity Paradox,6 which was published in April 2014 with the great help of my collaborator, Kristin Loberg, who has published many top-selling books.
This book has been the topic of multiple television, radio, print, and electronic media reports during the past several months, including in the United States, Australia, the United Kingdom, and Europe. In my latest State-of-the-Art paper on this topic, which was published as the lead article in the April 15, 2014 issue of JACC,5 I mentioned my book as a potential conflict of interest (COI). I had also given several lectures for the Coca-Cola Company (not on their sugary or non-sugary products, but rather on fitness and one on the obesity paradox and fitness, similar to this state of the art paper), so I also listed the Coca-Cola Company COI, which I considered extremely minor (less than 1% of my total 2013 income).
There were some comments suggesting that our JACC paper may have been biased by the fact that myself and two of my four co-authors cited a Cola-Company COI (the other two being consultants and receiving non-restricted educational and research grants), stating that we did not mention sugar as the cause of obesity (in fact, our research demonstrates that the fundamental cause of obesity is marked declines over the last 5 decades in physical activitynot sugar, fast foods, or other dietary items).
Regardless, our paper was not on sugar or other aspects of diet, but was rather on the prognosis in obesity, the obesity paradox, and the critical role of fitness to impact the relationship between adiposity and subsequent prognosis. My potential COI regarding my obesity paradox book was considerably greater (at least I am hoping that it will be), but this commenter brought it back to sugar, even making the case for the resemblance between the makers of sugary beverages and big tobacco, which seems to me to be quite a major stretch.
Perhaps the controversy of sugar, non-sugary beverages, and potential COIs in this area can be the subject of a future Straight Talk column.
- Osman AF, Mehra MR, Lavie CJ, et al. J Am Coll Cardiol. 2000;36:2126-31.
- Lavie CJ, Osman AF, Milani RV, Mehra MR. Am J Cardiol. 2003;91:891-4.
- Lavie CJ, Milani RV, Ventura HO. J Am Coll Cardiol. 2009;53:1925-32.
- Lavie CJ, Alpert MA, Arena R, et al. JACC Heart Fail. 2013;1:93- 102.
- Lavie CJ, McAuley PA, Church TS, et al. J Am Coll Cardiol. 2014;63:1345-54.
- Lavie CJ with Loberg K. The Obesity ParadoxWhen Thinner Means Sicker and Heavier Means Healthier. Hudson Street Press, April 3, 2014, New York, New York.
Carl J. Lavie, MD, is medical director of cardiac rehabilitation and director of exercise laboratories at the John Ochsner Heart and Valvular Institute at the University of Queensland School of Medicine in New Orleans. Dr. Lavie also works in the department of preventive medicine at the Pennington Biomedical Research Laboratory in Baton Rouge.
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