Weight & Risk of Death; Cancer & Vitamin D; Breakfast Cereal & Heart Disease; Causes of Malpractice; Risks of Surgery: Avoid Fridays!

Body Weight and Risk of Death

Few public health issues have become more controversial than the role of obesity in health and disease in the United States.  As the rates of obesity continue to spiral ever upwards in the US, obesity-related diseases have risen in tandem with an increasingly heavy population.  At the same time, remarkable progress in the treatment of diseases that, historically, have been the most formidable causes of early death in America have, it appears, blunted the death rates associated with may obesity-associated illnesses.  A compelling new study, just published in the Journal of the American Medical Association, delves deeper into the association between weight (both under- and overweight states) and death due to specific diseases.

Using data from two large, prospective studies (the National Health and Nutrition Examination Surveys, I and II) and vital statistics databases, death rates and causes of death for 2.3 millions adults were assessed in relation to body weight status.  Using body mass index (BMI) as a measure of body weight, this study provides some very intriguing conclusions although, at best, some of these conclusions are subject to ongoing debate, and require further clarification through additional research.

Looking at the effects of being overweight (BMI 25-29) and obese (BMI 30 or greater), significant differences in specific cause of death were identified for each group.  Being overweight was associated with a decreased risk of death due to non-cancer and non cardiovascular diseases, and failed to show any association with the risk of death due to cancer or cardiovascular illnesses.  Obesity, however, was associated with a significantly increased risk of death due to cardiovascular diseases, but was not associated with an increased risk of death due to cancer (overall) or other non-cardiovascular diseases.  However, when looking at cancers known to be associated with obesity (including cancers of the colon, rectum, breast, esophagus, uterus, ovary, kidney, and pancreas), there was, in fact, an increased risk of death due to these particular cancers among obese adults.  When looking at the combined data for both overweight and obese individuals, a significantly increased risk of death due to diabetes and kidney disease (which often results from diabetes), specifically, was identified.   

Much has been made, in the lay press, regarding the seemingly counterintuitive findings of this study with regards to underweight adults (BMI <18.5).  This study found that underweight individuals actually had an increased risk of death from non-cancer and non-cardiovascular diseases, when compared with normal weight adults, although no association was found between being underweight and the risk of death due to cancer or cardiovascular disease.  This finding, along with the findings noted for overweight and obese adults, has been lauded, by some, as proof that being overweight may actually be a healthy condition.  However, this is an overly simplistic assumption.  Indeed, both in this study and in many other public health studies, a large proportion of mortality associated with being underweight has been linked to the coexistence of chronic respiratory diseases (and, most notably, smoking-associated emphysema) which are, themselves, associated with a high risk of early death.  Also, improved treatments for diabetes, cardiovascular diseases (including coronary artery disease and high blood pressure) and, to a lesser extent, for cancer, have begun to yield improved survival rates in patients with these diseases, including among overweight and obese patients.    

In some cases, perhaps, when patients do become ill with life-threatening diseases, having a little extra (but not too much) “nutritional reserve” onboard may, hypothetically, be a good thing.  However, what is clear from this large study, and many others, is that increasing BMI, particularly at or above a BMI of 30, is linked to a significant increase in the risk of early mortality, most notably from cardiovascular diseases.  Likewise, the incidence of many diseases associated with both an increased risk of mortality and chronic disability also are known to rise in lock-step with increases in BMI.  These illnesses include diabetes, high blood pressure, kidney failure, coronary artery disease (and heart attacks), congestive heart failure, stroke, lung disease, obesity-related cancers (including pancreatic cancer, which remains one of the most lethal of all cancers), and arthritis, among others. 

It may well be the case that minimal-to-mild levels of increased body fat may afford some protection in patients who subsequently develop certain life-threatening illnesses, just as it is certainly true that many people who are seriously underweight have a low BMI due to the presence of one or more life-threatening co-existing illnesses.  (An accompanying study and editorial in the same journal confirms that a significant reduction in overall quality of life is associated with obesity-related disabilities; and quality of life, which is another important measure of overall health and well-being, is not directly reflected in studies looking only at mortality rates).   

Finally, as with all epidemiological studies that rely upon surveys and public health databases, intrinsic errors contained in such rather subjective sources of data can skew the accuracy of both the results and the conclusions from such studies, despite efforts to control for such inherent potential inaccuracies.  In taking the broad view of the abundant clinical research on the association between obesity and health, the overwhelming consensus is that remaining within a normal BMI range, remaining physically fit and active, and cutting saturated fats and meat to a minimum in your diet are all associated with the best chance of leading a long and healthy life.  Being too heavy or excessively thin, all other things being equal, are probably not in our best interests, health-wise. 

Briefly… 

Annals of Surgery—A retrospective study of non-emergent surgeries performed in Veterans Administration hospitals revealed a small, but significant, increase in postoperative deaths among inpatients undergoing non-emergent operations on Fridays, when compared to similar patients undergoing comparable surgeries on Mondays, Tuesdays and Wednesdays.  As with recent studies showing worse outcomes for patients admitted over the weekend with an acute heart attack, the findings of this retrospective study suggest (but do not prove) that the diminished staffing present in most medical centers on the weekends may have an adverse impact on patient care outcomes. 

Archives of Internal Medicine—A retrospective study of medical malpractice claims completed between 1984 and 2004 revealed that, in 240 total cases, 72% were associated with errors in medical judgment, 70% involved errors in communication and teamwork, and 58% included technical errors in the delivery of care.  Failures in teamwork and communication generally revolved around inadequate supervision of interns and residents by attending physicians, and inadequate “hand-off” of patients between teams of physicians.  These teamwork-related failures were far more likely to be found among interns and residents than among the attending doctors (54% of cases vs. 7%, respectively).  This study has important implications for all of us involved in training the next generation of physicians and surgeons and, especially, for all patients. 

Archives of Internal Medicine—A diet rich in whole grains and fiber, in addition to other “heart-healthy” lifestyle factors, has been shown to reduce the risk of heart disease and high blood pressure.  A new, prospective study of more than 21,000 physician-participants takes a look at the impact of breakfast cereals on another major killer, congestive heart failure (a condition that arises when the heart can no longer effectively pump blood to the body).  After an average follow-up period of 19.6 years, this study found that high levels of whole grain breakfast cereal consumption (but not highly-refined or processed cereals) were associated with a significant reduction in the risk of congestive heat failure in this otherwise generally healthy population of physicians. 

Journal of the National Cancer Institute—Despite a tremendous amount of research on the topic (and an area of particular interest to me), there is very little data to support a beneficial effect of specific nutrients and dietary supplements in reducing the risk of cancer.  Vitamin D has been extensively studied, both from the perspective of adding Vitamin D supplements to the diet and by directly measuring blood levels of this vitamin, for any cancer-preventing properties that may be present.  With the exception of colorectal cancer, most of the data regarding Vitamin D has been unimpressive.  With respect to colorectal cancer, however, the clinical data is, at best, mixed with respect to the vitamin’s ability to reduce the risk of developing colorectal cancer.  A new, prospective study from the National Cancer Institute followed more than 16,000 adults from 1988 through 2000.  All study participants had blood levels of Vitamin D measured when they first entered the study.  A total of 536 cancer-related deaths occurred during the study period.  Overall, cancer-related deaths did not vary according to the levels of Vitamin D in the blood.  However, when the patients who died from colorectal cancer, specifically, were studied, a very significant reduction in the risk of dying from colorectal cancer was found among those study participants with the highest levels of Vitamin D in their blood.   A study of this type cannot completely eliminate the possibility that other non-measured factors might have played some role in the published findings.   However, this very high quality, prospective study, with a long period of study participant follow-up, strongly suggests that high Vitamin D levels in the blood may be moderately protective against colorectal cancer. 

Disclaimer:  As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity. 

Dr. Robert Wascher is an oncologic surgeon, professor of surgery, and a widely published author.  He is the Director of the Division of Surgical Oncology at Newark Beth Israel Medical Center. 

Send your feedback to Dr. Wascher at rwascher@doctorwascher.net
 

http://www.sbhcs.com/hospitals/newark_beth_israel/mservices/oncology/surgical.html
 

Copyright 2007. Robert A. Wascher, MD, FACS. All rights reserved.