Thursday, February 7, 2013
Obesity and the perils of ping-pong science
According to a widely circulated op-ed in yesterday's New York Times by Paul Campos, a law professor at the University of Colorado with whom I don't believe I have ever managed to agree on anything, our "fear" of fat--namely, epidemic obesity--is, in a word, absurd.
Prof. Campos is the author of a book titled The Obesity Myth, and has established something of a cottage industry for some time contending that the fuss we make about epidemic obesity is all some government-manufactured conspiracy theory, or a confabulation serving the interests of the weight-loss-pharmaceutical complex.
In this instance, the op-ed was reacting to a meta-analysis, published in JAMA, and itself the subject of extensive media attention, indicating that mortality rates go up as obesity gets severe, but that mild obesity and overweight are actually associated with lower overall mortality than so-called "healthy" weight. This study, debunked for important deficiencies by many leading scientists around the country, and with important limitations acknowledged by its own authors, was treated by Prof. Campos as if a third tablet on the summit of Mount Sinai.
We'll get into the details of the meta-anlysis shortly, but first I'd like to say: Treating science like a ping-pong ball is what's absurd, and what scares the hell out of me. Treating any one study as if its findings annihilate the gradual, hard-earned accumulation of evidence over decades is absurd, and scares the hell out of me. Iconoclasts who get lots of attention just by refuting the conventional wisdom, and who are occasionally and importantly right, but far more often wrong, are often rather absurd, and scare the hell out of me.
And so does the obesity epidemic.
As for the meta-analysis, a study designed to pool the results of other studies, it is in some ways complex and in some ways quite sophisticated. But in many important ways, it is very crude.
A meta-analysis is never any better than the studies it is aggregating. In this case, those studies merely looked at the population-level association between the body mass index, itself a rather crude measure of body fat, which is what really matters, and death rate.
The first, obvious limitation of this study is that it examined mortality (death) but not morbidity (illness). The Global Burden of Disease Study, recently published in The Lancet and sponsored by the World Health Organization, the World Bank, and the Bill and Melinda Gates Foundation, is widely acknowledged as one of the most comprehensive epidemiologic assessments in history. What it shows, among countries around the world, is that we are living longer, but sicker. Thanks to the cutting edge of biomedical advance, we can often forestall death; but high-tech medicine is not remotely as useful for cultivating health and vitality.
So, it's no surprise that overweight and mild obesity do not increase mortality. They could cause an enormous burden of chronic disease and still not do so.
But why would overweight and mild obesity be associated with a lower rate of mortality, as the meta-analysis suggests? For one thing, when people get sick, they generally lose weight. The new study was in no way adjusted to exclude from the analysis people who were thin because they were sick. We have long had evidence that among older people, hanging onto weight is associated with better outcomes than losing weight.
Second, in a society where a vast majority of the whole population is either overweight or obese, who isn't? Well, to some extent, thin and healthy people. But also, along with those who have chronic disease, there are smokers (the meta-analysis only partly corrected for this), alcoholics, people with eating disorders, people who use illicit drugs, people with severe depression, and so on. There is an enormous difference between being lean because of eating well and being physically active, and being lean because of anorexia nervosa or routine cocaine use. The meta-analysis was blind to any such distinctions.
And, lastly for now (there are more elements to this argument, but I don't have time to write the whole manifesto right now, and you probably don't have time to read it!), there is the fact that while overall obesity rates in the U.S. are showing signs of stabilizing, the rate of severe obesity, the very variety even this meta-analysis associates with a 30% or more increase in mortality risk, is "skyrocketing."
There are two implications of this. First, it is ever less useful to ask, "How many of us are overweight?" and ever more important to start asking, "How overweight are the many of us?" And second, since as a society we are getting ever heavier, it stands to reason that those who manage to remain only overweight are, in fact, doing something right, and deriving health benefits accordingly.
The danger in using the new study to renounce concerns about weight as Campos suggests is that we invite weight gain, which will take us from overweight, to mildly obese, to more severely so. Those who are overweight but stably so aren't ignoring their health and weight; they are controlling them.
As for why those prepared to toss out everything we thought we knew about the health risks of obesity are not just wrong, but alarmingly so, let me count the reasons!
1) As noted, the Global Burden of Disease report indicates that mortality is not the real menace, it's morbidity. Obesity is consistently, powerfully associated with the risk of chronic disease.
2) When I was in medical school, we learned about "adult-onset" diabetes. That is now called "Type 2" diabetes because it occurs routinely in kids as well. It occurs routinely in kids because of epidemic childhood obesity.
3) The CDC is projecting that by mid-century, up to 1 in 3 Americans will be diabetic, due almost entirely to epidemic obesity. The trend is already well under way.
4) For those doubting, as Prof. Campos seems to, that obesity is the cause of all this diabetes and chronic disease, there is the Diabetes Prevention Program, which demonstrates that a 7% loss in body weight produces a 58% reduction in the development of diabetes among high-risk adults.
5) Studies spanning 20 years (1, 2, 3, 4) show a decisive association between healthful lifestyle practices, with resulting weight control, and a dramatic reduction in both chronic morbidity and premature mortality.
6) Unlike Prof. Campos, who is a lawyer, I am a doctor, I take care of patients, including those wrestling with weight control. Over 20 years, I have seen personally the changes in health and vitality when people who are obese become lean through the application of sensible and sustainable lifestyle practices.
7) My colleagues in pediatrics tell me routinely they are not only seeing Type 2 diabetes, but also fatty liver disease in overweight and obese children. When the obesity goes away, so do these ominous conditions.
8) A 35% increase in the rate of stroke has been reported among 5-to-14-year-olds in the U.S., and the only smoking gun on the scene to account for it is epidemic childhood obesity.
9) A study in roughly a million people that did control for chronic illness found a strong and consistent association between the body mass index and the risk of death and cancer.
10) The BMI is known to be a crude measure that does not account for whether weight is muscle or fat, and if fat, where on the body it resides. The evidence that excess body fat particularly around the middle is harmful is indisputable.
I guess, if Campos is right, this is all a myth. But since I actually see the evidence of it personally, as do many of my colleagues, it must be more than just a myth; it must be some kind of mass hallucination. Those, I think, are our choices. We are having a shared, population-level hallucination about the implications of epidemic obesity; or Prof. Campos is wrong. Choose.
Iconoclasts who see what the rest of the world overlooks are occasionally right. Copernicus and Galileo were right. Newton and Einstein were right. But the company is rarefied.
Most of the time, those who refute conventional wisdom profit from notoriety at our collective expense and are, in time, proven to be wrong. Immunizations are not perfectly safe, but those who have propagated conspiracy theories that are in turn spawning global resurgences of measles and pertussis aren't doing us any favors. Atkins didn't really help us by substituting for a narrow, obsessive fixation on dietary fat a comparably narrow, comparably obsessive preoccupation with carbohydrate.
And, here's an example, intimately familiar to me and perhaps more vivid than the rest, about the hazards of ping-pong science. For years the party line, based on the slow accumulation of evidence, was that hormone replacement therapy at menopause would reduce chronic disease and premature mortality risk. Then, two randomized clinical trials called HERS and the WHI refuted this.
The media made hay with these "the conventional wisdom was wrong!" findings, as they tend to do. The result was that we didn't seek a balanced truth, but went from pole-to-pole, from loving HRT to reviling it. There was baby and bathwater, but we just lumped them together and sent them down a collective drain. Women abandoned HRT in droves.
Who cares? We all should. Colleagues and I have conducted an analysis, soon to be published, demonstrating that tens of thousands of women have died prematurely as a result of this mass avoidance of judicious use of hormone replacement. It's neither all good, nor all bad, it's good when the right women use the right preparation at the right time in the right way for the right reasons. But what boring headlines that would make! So much more exciting to proclaim: "Everybody was wrong! There's another conspiracy!" Much more exciting, but almost never right, and all too often lethal.
We can, of course, become unduly focused on body weight. In fact, as a culture we do so routinely. Weight is not the issue; health is the issue. It is possible to be heavier and healthy, or thinner and sick. We should keep our eyes on the prize. And the new meta-analysis may suggest that the range of "normal" for weight could be expanded, although it by no means proves it.
But at the population level, epidemic obesity is incontrovertibly established as a clear and all-but-omnipresent danger. It is absurd to suggest otherwise. And it's those who do so, who play ping-pong with science because of misguided bias or motivated self-interest, who threaten to forestall the societal action needed to turn this toxic tide, who frighten the hell out of me!
David L. Katz, MD, FACP, MPH, FACPM, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care. He is a board certified specialist in both Internal Medicine, and Preventive Medicine/Public Health, and Associate Professor (adjunct) in Public Health Practice at the Yale University School of Medicine. He is the Director and founder (1998) of Yale University's Prevention Research Center; Director and founder of the Integrative Medicine Center at Griffin Hospital (2000) in Derby, Conn.; founder and president of the non-profit Turn the Tide Foundation; and formerly the Director of Medical Studies in Public Health at the Yale School of Medicine for eight years. This post originally appeared on his blog at The Huffington Post.
Contact ACP Internist
Send comments to ACP Internist staff at email@example.com.
- How should we calculate influenza vaccine effectiv...
- QD: News Every Day--Study finds financial bias doe...
- Larry the vomit simulator
- Preventing shingles
- QD: News Every Day--Adults widely consume suppleme...
- Is it safe?
- Is colonoscopy the best colon cancer screening tes...
- Progress notes are a poor match between billing an...
- QD: News Every Day--Empathetic doctors get rewarde...
- New norovirus strain strikes the U.S.
Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.
And Thus, It Begins
Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.
Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.
Controversies in Hospital
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Richmond, Va., with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).
db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.
Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.
Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.
Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.
Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.
David Katz, MD
David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.
Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.
Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.
Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.
Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.
Rob Lamberts, MD, ACP Member, a med-peds and general practice internist, returns with "volume 2" of his personal musings about medicine, life, armadillos and Sasquatch at More Musings (of a Distractible Kind).
David M. Sack, MD, FACP, practices general gastroenterology at a small community hospital in Connecticut. His blog is a series of musings on medicine, medical care, the health care system and medical ethics, in no particular order.
Reflections of a Grady
Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.
The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.
Technology in (Medical)
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.
Peter A. Lipson,
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.
Why is American Health Care So Expensive?
Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.
World's Best Site
Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.
Other blogs of note:
American Journal of
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.
Michael Benjamin, MD, ACP member, doesn't accept industry money so he can create an independent, clinician-reviewed space on the Internet for physicians to report and comment on the medical news of the day.
The Public Library of Science's open access materials include a blog.
One of the most popular anonymous blogs written by an emergency room physician.