Obesity paradox

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As obesity paradox ( English obesity paradox ), even reverse or paradoxical epidemiology called, refers to the epidemiological phenomenon that overweight or obese patients with some diseases better chances of survival than normal weight.

description

In certain diseases, obesity can - statistically speaking - be life-prolonging.

A large number of clinical studies, for example the Framingham Heart Study , have shown that a high body mass index (BMI) correlates with serious diseases such as diabetes mellitus , heart failure , arteriosclerosis , stroke or breast cancer . Obesity is a clear risk factor that significantly reduces life expectancy.

In contrast, a number of epidemiological studies have shown that patients - i.e. people who are already ill - with an increased BMI obviously have a higher life expectancy than patients of normal weight. Studies have found an obesity paradox for the following diseases:

However, this paradox is often misinterpreted to mean that being overweight is better than normal weight. The obesity paradox, however, only applies to people who are already ill, and these people already statistically have a shortened life expectancy due to their illness. In the case of heart failure, it is better to avoid the disease by having a normal weight than trying to survive with being overweight.

First, the obesity paradox was identified in chronic dialysis patients. In all subsequent studies, the patients with the lowest body mass index had the worst prognosis.

In the meantime, studies of acute patients ( sepsis ) are also available, according to which obese patients also have a survival advantage.

The obesity paradox was first described in 1999.

Take heart failure as an example

When evaluating over 100,000 patient files from the Acute Decompensated Heart Failure National Registry (ADHERE), it was found that the clinical mortality rate for patients with a BMI of 16.0 to 23.6 kg / m² was 6.3%. It decreased linearly with increasing BMI. Clinical mortality in obese patients with a BMI of 33.4 to 60 kg / m² was only 2.4%. This difference persisted even after correcting risk factors such as age, gender, blood urea, blood pressure , creatinine , sodium , heart rate, and resting dyspnea .

Possible causes of the paradox

The study results were initially discussed extremely controversially. For one, the existence of the obesity paradox has been questioned. One argument against the obesity paradox is that chronic patients with the lowest BMI are usually the most seriously ill. In many diseases, such as AIDS or cancer , the disease-related weight loss also occurs in the end stage. These confusion effects would falsify the study results. A typical confounder is tobacco smoking , which reduces the BMI but significantly increases mortality . But even after the studies were corrected for confounders (e.g. age, gender, severity of the disease), the obesity paradox persisted. It is now widely accepted that a higher BMI offers a survival advantage for some chronic diseases.

However, the cause of the obesity paradox is largely unclear. Despite great research efforts, the obesity paradox is still unexplained. Various hypotheses are discussed.

A possible cause could be the larger metabolic reserves of obese patients, which are advantageous, for example, in the case of tumor cachexia caused by cancer . Certain cytokines such as TNF-α or interleukin-6 , which are involved in cachexia, are obviously better absorbed in the adipose tissue of obese patients , for example through the soluble TNF-α receptor. Possibly the increased amount of lipoproteins in the serum of overweight patients is beneficial in combating circulating endotoxins . The plasma levels of B-type natriuretic peptide (BNP) and N-terminal proBNP, which are reduced in overweight people, are also discussed as possible causes of the obesity paradox. Obese patients may be better cared for or monitored by the nursing staff, as problems are more likely to arise with them. Broken bones are a common cause of death in old age. However, being overweight can protect against broken bones. As part of the Selfish Brain study, obesity researcher Prof. Achim Peters found that being fat can be a result of dealing with stress and that this reduces the permanently harmful high cortisol level.

The problem is that almost all studies are retrospective observational studies.

further reading

Individual evidence

  1. ↑ M. Bluher: Fat tissue and long life. In: Obesity facts. Volume 1, Number 4, 2008, pp. 176-182, ISSN  1662-4025 . doi : 10.1159 / 000145930 . PMID 20054178 . (Review).
  2. ↑ L. Fontana, S. Klein: Aging, adiposity, and calorie restriction. In: JAMA . Volume 297, Number 9, March 2007, pp. 986-994, ISSN  1538-3598 . doi : 10.1001 / jama.297.9.986 . PMID 17341713 . (Review).
  3. ^ A. Peeters, JJ Barendregt a. a .: Obesity in adulthood and its consequences for life expectancy: a life-table analysis. In: Annals of internal medicine . Volume 138, Number 1, January 2003, pp. 24-32, ISSN  1539-3704 . PMID 12513041 .
  4. ↑ EE Calle, MJ Thun a. a .: Body-mass index and mortality in a prospective cohort of US adults. In: The New England journal of medicine . Volume 341, Number 15, October 1999, pp. 1097-1105, ISSN  0028-4793 . doi : 10.1056 / NEJM199910073411501 . PMID 10511607 .
  5. ↑ a b c R. Arena, CJ Lavie: The obesity paradox and outcome in heart failure: is excess bodyweight truly protective? In: Future cardiology. Volume 6, Number 1, January 2010, pp. 1-6, ISSN  1744-8298 . doi : 10.2217 / fca.09.158 . PMID 20014982 . (Review).
  6. ↑ A. Oreopoulos, R. Padwal et al. a .: Body mass index and mortality in heart failure: a meta-analysis. In: American Heart Journal . Volume 156, Number 1, July 2008, pp. 13-22, ISSN  1097-6744 . doi : 10.1016 / y.ahj.2008.02.014 . PMID 18585492 . (Review).
  7. ^ A. Romero-Corral, VM Montori et al. a .: Association of bodyweight with total mortality and with cardiovascular events in coronary artery disease: a systematic review of cohort studies. In: The Lancet . Volume 368, Number 9536, August 2006, pp. 666-678, ISSN  1474-547X . doi : 10.1016 / S0140-6736 (06) 69251-9 . PMID 16920472 . (Review).
  8. ↑ HJ Buettner, C. Mueller u. a .: The impact of obesity on mortality in UA / non-ST-segment elevation myocardial infarction. In: European heart journal. Volume 28, Number 14, July 2007, pp. 1694-1701, ISSN  0195-668X . doi : 10.1093 / eurheartj / ehm220 . PMID 17576661 .
  9. ↑ S. Uretsky, FH Messerli u. a .: Obesity paradox in patients with hypertension and coronary artery disease. In: The American journal of medicine. Volume 120, Number 10, October 2007, pp. 863-870, ISSN  1555-7162 . doi : 10.1016 / j.amjmed.2007.05.011 . PMID 17904457 .
  10. ^ W. Galal, YR van Gestel u. a .: The obesity paradox in patients with peripheral arterial disease.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. In: Chest. Volume 134, Number 5, November 2008, pp. 925-930, ISSN 0012-3692 . doi : 10.1378 / chest.08-0418 . PMID 18641109 .@1@ 2Template: Dead Link / chestjournal.chestpubs.org   
  11. ↑ M. Khalangot, M. Tronko et al. a .: Body mass index and the risk of total and cardiovascular mortality among patients with type 2 diabetes: a large prospective study in Ukraine. In: Heart. Volume 95, Number 6, March 2009, pp. 454-460, ISSN  1468-201X . doi : 10.1136 / hrt.2008.150524 . PMID 18697804 .
  12. ↑ D. Schmidt, A. Salahudeen: The obesity-survival paradox in hemodialysis patients: why do overweight hemodialysis patients live longer? In: Nutrition in clinical practice: official publication of the American Society for Parenteral and Enteral Nutrition. Volume 22, Number 1, February 2007, pp. 11-15, ISSN  0884-5336 . PMID 17242449 . (Review).
  13. ↑ a b The obesity paradox - overweight people survive acute heart failure more often. ( Memento of the original from February 12, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Deutsches Ärzteblatt. 9 January 2007 @1@ 2Template: Webachiv / IABot / www.aerzteblatt.de
  14. ↑ a b W. Druml: "The fatter - the better?" - Does a high body mass offer a survival advantage for acute patients?  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. In: Wiener Klinische Wochenschrift. Volume 122, Number 1-2, pp. 8-10. doi : 10.1007 / s00508-009-1293-5 PMID 20177853@1@ 2Template: Dead Link / resources.metapress.com  
  15. ↑ B. Wurzinger, MW Dünser u. a .: The association between body-mass index and patient outcome in septic shock: a retrospective cohort study. In: Wiener Klinische Wochenschrift. Volume 122, Number 1-2, January 2010, pp. 31-36, ISSN  1613-7671 . doi : 10.1007 / s00508-009-1241-4 . PMID 20177857 .
  16. ↑ E. Fleischmann, N. Teal et al. a .: Influence of excess weight on mortality and hospital stay in 1346 hemodialysis patients. In: Kidney International . Vol. 55, 1999, pp. 1560-1567. doi : 10.1046 / j.1523-1755.1999.00389.x . PMID 10201023 .
  17. ↑ DS Schmidt, AK Salahudeen: Obesity-survival paradox-still a controversy? In: Seminars in dialysis. Volume 20, 2007, pp. 486-492, ISSN  0894-0959 . doi : 10.1111 / j.1525-139X.2007.00349.x . PMID 17991192 . (Review).
  18. ↑ GC Fonarow, P. Srikanthan u. a .: An obesity paradox in acute heart failure: analysis of body mass index and inhospital mortality for 108,927 patients in the Acute Decompensated Heart Failure National Registry. In: American Heart Journal . Volume 153, Number 1, January 2007, pp. 74-81, ISSN  1097-6744 . doi : 10.1016 / y.ahj.2006.09.007 . PMID 17174642 .
  19. ↑ A. Habbu, NM Lakkis, H. Dokainish: The obesity paradox: fact or fiction? In: The American journal of cardiology. Volume 98, Number 7, October 2006, pp. 944-948, ISSN  0002-9149 . doi : 10.1016 / j.amjcard.2006.04.039 . PMID 16996880 . (Review).
  20. ^ PA Ades, PD Savage: The obesity paradox: perception vs knowledge. In: Mayo Clinic proceedings. Volume 85, Number 2, February 2010, pp. 112-114, ISSN  1942-5546 . doi : 10.4065 / mcp.2009.0777 . PMID 20118385 . PMC 2813817 (free full text).
  21. ↑ a b T. Dorner: The Obesity Paradox  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www.sge-ssn.ch  
  22. ↑ a b P. G. von Grätz: In the intensive care unit, life is much longer. In: Doctors newspaper. April 12, 2010
  23. ^ V. Mohamed-Ali, S. Goodrick et al. a .: Production of soluble tumor necrosis factor receptors by human subcutaneous adipose tissue in vivo. In: American Journal of Physiology-Endocrinology and Metabolism . 1999; 277: E971-E975, PMID 10600783 .
  24. ↑ The Obesity Paradox. In: Diabetes Journal. dated April 6, 2010
  25. ↑ MR Mehra, PA Uber u. a .: Obesity and suppressed B-type natriuretic peptide levels in heart failure. In: Journal of the American College of Cardiology. Volume 43, Number 9, May 2004, pp. 1590-1595, ISSN  0735-1097 . doi : 10.1016 / j.jacc.2003.10.066 . PMID 15120816 .
  26. ↑ TE Dorner, A. Rieder: The obesity paradox or reverse epidemiology: high body weight as a protective factor in certain chronic conditions? (PDF; 200 kB) In: German Medical Weekly. Volume 135, Number 9, 2010, pp. 413-418. doi : 10.1055 / s-0030-1249178
  27. ↑ Peters, A .: The myth of overweight. Why fat people live longer. What weight has to do with stress - surprising findings from brain research . ISBN 978-3-570-10149-0 , C. Bertelsmann Verlag 2013.

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