Central obesity 54712 225358118 2008-07-13T07:30:17Z 68Kustom 6357289 /* Sit ups myth */ {{weasel}} {{DiseaseDisorder infobox | Name = Central obesity | ICD10 = E66 | ICD9 = {{ICD9|278}} | }} [[Image:Central Obesity 008.jpg|thumb|Central obesity, or "belly fat"]] '''Central obesity''', the "apple-shaped" [[obesity]] commonly referred to as '''belly fat''', is the accumulation of [[visceral fat]] ([[adipose tissue|fat]] deposited between the internal organs in the torso) resulting in an increase in waist size. There is a strong correlation between central obesity and [[cardiovascular disease]].<ref name=Yusuf2004>{{cite journal | author=Yusuf S, Hawken S, Ounpuu S, Dans T, Avezum A, Lanas F, McQueen M, Budaj A, Pais P, Varigos J, Lisheng L, INTERHEART Study Investigators. | title=Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study.|journal=[[The Lancet|Lancet]] | year=2004 | pages=937–52 | volume=364 | pmid=15364185 | doi=10.1016/S0140-6736(04)17018-9}}</ref> While central obesity can be obvious just by looking at the naked body (see the picture), the severity of central obesity is determined by taking waist and hip measurements. The absolute waist circumference (>{{convert|102|cm|in}} in men and >{{convert|88|cm|in}} in women) and the [[waist-hip ratio]] (>0.9 for men and >0.85 for women)<ref name=Yusuf2004/> are both used as measures of central obesity. In the scientific experiment known as the [[National Health and Nutrition Examination Survey]] (NHANES III), which included almost 15,000 people, waist circumference explained obesity-related health risk significantly better than the [[body mass index]] (or BMI) when [[metabolic syndrome]] was taken as an outcome measure.<ref>{{cite journal |author=Janssen I, Katzmarzyk PT, Ross R |title=Waist circumference and not body mass index explains obesity-related health risk |journal=Am. J. Clin. Nutr. |volume=79 |issue=3 |pages=379–84 |year=2004 |pmid=14985210 |url=http://www.ajcn.org/cgi/content/abstract/79/3/379 |doi=10.1185/030079906X159489}}</ref> == Health risks == Central obesity is associated with a statistically higher risk of [[heart disease]], [[hypertension]], [[insulin resistance]], and [[diabetes mellitus]] type 2 (see below). Belly fat is a [[Metabolic syndrome#Signs and symptoms|symptom of metabolic syndrome]], and is an indicator used in the [[Metabolic syndrome#Diagnosis|diagnosis of that disorder]].<ref>Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. ''Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III).'' JAMA 2001;285:2486-97. PMID 11368702.</ref><ref name="Grundy">[http://circ.ahajournals.org/cgi/reprint/109/3/433.pdf Grundy SM, Brewer HB, Cleeman JI, Smith SC, Lenfant D, for the Conference Participants. Definition of metabolic syndrome: report of the National, Heart, Lung, and Blood Institute/American Heart Association conference on scientific issues related to definition.] Circulation. 2004;109:433-438.</ref><ref>[http://www.americanheart.org/presenter.jhtml?identifier=4756 American Heart Association's description of Syndrome X]</ref> Central obesity can be a feature of [[lipodystrophy|lipodystrophies]], a group of diseases which is either [[genetic disorder|inherited]], or due to secondary causes (often [[protease inhibitor (pharmacology)|protease inhibitor]]s, a group of [[medication]]s against [[AIDS]]). Central obesity is a symptom of [[Cushing's syndrome]] (which may cause it)<ref>{{cite journal |author=Bujalska IJ, Kumar S, Stewart PM |title=Does central obesity reflect "Cushing's disease of the omentum"? |journal=Lancet |volume=349 |issue=9060 |pages=1210–3 |year=1997 |pmid=9130942 |doi=10.1016/S0140-6736(96)11222-8}}</ref>. Central obesity is also common in patients with [[polycystic ovary syndrome]] (PCOS). === Relationship with diabetes === There are numerous theories as to the exact cause and mechanism in type 2 diabetes. Central obesity is known to predispose individuals for insulin resistance. Abdominal fat is especially active hormonally, secreting a group of hormones called [[adipokine]]s that may possibly [[Impaired glucose tolerance|impair glucose tolerance]]. [[Insulin resistance]] is a major feature of [[diabetes mellitus type 2]] (T2DM), and central obesity is correlated with both insulin resistance and T2DM itself.<ref>Duman BS, Turkoglu C, Gunay D, Cagatay P, Demiroglu C, Buyukdevrim AS. The interrelationship between insulin secretion and action in type 2 diabetes mellitus with different degrees of obesity: evidence supporting central obesity. Diabetes Butr Metab. 16(4): 243-250, 2003.</ref><ref>Gabriely, I., Ma, X. H., Yang, X. M., Atzmon G, Rajala MW, berg AH, Sherer P, Rossetti L, Barzilai N. Removal of visceral fat prevents insulin resistance and glucose intolerance of aging: an adipokine-mediated process? Diabetes. 51: 2951–2958, 2002.</ref> Increased [[adiposity]] (obesity) raises serum resistin levels<ref name=Asensio2004>Asensio, C., Cettour-Rose, P., Theander-Carrillo, C., Rohner-Jeanrenaud, F. and Muzzin, P. Changes in glycemia by leptin administration or high-fat feeding in rodent models of obesity/type 2 diabetes suggest a link between resistin expression and control of glucose homeostasis. Endocrinology. 145: 2206–2213, 2004.</ref><ref>Degawa-Yamauchi MBJE, Juliar BE, Watson W, Kerr K, Jones RM, Zhu Q & Considine RV. Serum resistin (FIZZ3) protein is increased in obese humans. Journal of Clinical Endocrinology and Metabolism. 88: 5452–5455, 2003.</ref><ref>Lee, J. H., Bullen, Jr, J. W., Stoyneva, V. L. and Mantzoros, C. S. Circulating resistin in lean, obese and insulin-resistant mouse models: lack of association with insulinemia and glycemia. Am. J. Physiol. Endocrinol. Metab. 288: E625–E632, 2005.</ref><ref>Vendrell J, Broch M, Vilarrasa N, Molina A, Gomez JM, Gutierrez C, Simon I, Soler J & Richart C. Resistin, adiponectin, ghrelin, leptin, and proinflammatory cytokines: relationships in obesity. Obesity Research. 12: 962–971, 2004.</ref>, which in turn directly correlate to insulin resistance<ref>Hirosumi J, Tuncman G, Chang L, Gorgun CZ, Uysal KT, Maeda K, Karin M, Hotamisligil GS. A central role for JNK in obesity and insulin resistance. Nature. 420: 333-336, 2002. [http://www.hsph.harvard.edu/GSH-LAB/tnf-ins.html]</ref><ref>Rajala, M. W., Qi, Y., Patel, H. R., Takahashi N, Banerjee R, Pajvani UB, Sinha MK, Gingerich RL, Scherer PE, Ahima RS. Regulation of resistin expression and circulating levels in obesity, diabetes, and fasting. Diabetes. 53: 1671–1679, 2004.</ref><ref>Silha JV, Krsek M, Skrha JV, Sucharda P, Nyomba BL and Murphy LJ. Plasma resistin, adiponectin and leptin levels in lean and obese subjects: correlations with insulin resistance. Eur. J. Endocrinol. 149: 331-335, 2003.</ref><ref>Smith, S. R., Bai, F., Charbonneau, C., Janderova, L. and Argyropoulos, G. A promoter genotype and oxidative stress potentially link resistin to human insulin resistance. Diabetes 52, 1611–1618, 2003.</ref>. Studies have also confirmed a direct correlation between resistin levels and T2DM.<ref name=Asensio2004/><ref>Fujinami, A., Obayashi, H., Ohta, K, Ichimura T, Nishimura M, Matsui H, Kawahara Y, Yamazaki M, Ogata M, Hasegawa G, Nakamura N, Yoshikawa T, Nakano K, Ohta M. Enzyme-linked immunosorbent assay for circulating human resistin: resistin concentrations in normal subjects and patients with type 2 diabetes. Clin. Chim. Acta. 339: 57–63, 2004.</ref><ref>McTernan, P. G., Fisher, F. M., Valsamakis, G, Chetty R, Harte A, McTernan CL, Clark PM, Smith SA, Barnett AH, Kumar S. Resistin and type 2 diabetes: regulation of resistin expression by insulin and rosiglitazone and the effects of recombinant resistin on lipid and glucose metabolism in human differentiated adipocytes. J. Clin. Endocrinol. Metab. 88: 6098–6106, 2003.</ref><ref>Steppan CM, Bailey ST, Bhat S, Brown EJ, Banerjee RR, Wright CM, Patel HR, Ahima RS, Lazar MA. The hormone resistin links obesity to diabetes. Nature. 409:307-312, 2001.</ref>. And it is waistline adipose tissue (central obesity) which seems to be the foremost type of fat deposits contributing to rising levels of serum resistin.<ref>McTernan, C. L., McTernan, P. G., Harte, A. L., Levick, P. L., Barnett, A. H. and Kumar, S. Resistin, central obesity, and type 2 diabetes. Lancet. 359: 46–47, 2002.</ref><ref>McTernan, P. G., McTernan, C. L., Chetty, R, Jenner K, Fisher FM, Lauer MN, Crocker J, Barnett AH, Kumar S. Increased resistin gene and protein expression in human abdominal adipose tissue. J. Clin. Endocrinol. Metab. 87: 2407, 2002.</ref> Conversely, serum resistin levels have been found to ''decline'' with decreased adiposity following [[medical]] treatment.<ref>Valsamakis, G., McTernan, P. G., Chetty, R, Al Daghri N, Field A, Hanif W, Barnett AH, Kumar S. Modest weight loss and reduction in waist circumference after medical treatment are associated with favourable changes in serum adipocytokines. Metab. Clin. Exp. 53:430–434, 2004. </ref> == Causes == The main causes of central obesity are [[overeating]] and a [[sedentary lifestyle]]. Hypercortisolism, such as in [[Cushings syndrome]] also leads to central obesity. == Prevention and treatments == Performing adequate [[aerobic exercise]] and eating a [[healthy diet]] prevent central obesity, and [[Weight loss|losing weight]] via these methods is the main way to reverse the condition. Adjunctive therapies which may be prescribed by a physician are [[orlistat]] or [[sibutramine]]. In the presence of [[diabetes mellitus|diabetes mellitus type 2]], the physician might instead prescribe [[metformin]] and [[thiazolidinedione]]s ([[rosiglitazone]] or [[pioglitazone]]) as [[anti-diabetic drug]]s rather than [[sulfonylurea]] derivatives. Thiazolidinediones may cause slight weight gain but decrease [[visceral fat|"pathologic" abdominal fat]], and therefore may be prescribed for diabetics with central obesity.<ref>{{cite journal |author=Fonseca V |title=Effect of thiazolidinediones on body weight in patients with diabetes mellitus |journal=Am. J. Med. |volume=115 Suppl 8A |issue= |pages=42S–48S |year=2003 |pmid=14678865 |doi=10.1016/j.amjmed.2003.09.005}}</ref> === Sit-ups myth === There is a common misconception that spot exercise (that is, exercising a specific muscle or location of the body) most effectively burns fat at the desired location. But this is not the case. Spot exercise is beneficial for building specific muscles, but it has little effect on fat in that area of the body, or on the body's distribution of body fat. The same thing applies to sit-ups and belly fat. [[Sit-ups]] and other [[abdominal exercises]] are useful in building the [[abdomen#Muscles of the abdominal wall|abdominal muscles]], but they have little effect on the [[adipose tissue]] located there.<ref>{{cite web |url= http://www.mayoclinic.com/health/belly-fat/MC00054 |title= Belly fat in men: What you need to know |accessdate= 2008-04-07 |author= Michael Jensen, M.D. |date= 2007-01-19 |publisher= Mayoclinic.com |quote= Sit-ups will make your abdominal muscles stronger, sure. And, you may look thinner by building your abdominal muscles because you can hold in your belly fat better. But strengthening your stomach muscles alone will not specifically reduce belly fat. }}</ref> == Slang terms == There are some slang terms used to refer to central obesity, and to people who have it. There is little scientific evidence that [[beer]] drinkers are more prone to abdominal obesity, despite it being known colloquially as "beer belly" or "beer gut". "[[Love handles]]" is a colloquial term for a layer of [[adipose tissue|fat]] that is deposited around a person's midsection, especially visible on the sides over the [[abdominal external oblique muscle]]. "[[Muffin top]]" is a generally [[pejorative]] term used for a person whose flabby midsection spills over the waistline of his or her pants in a manner that resembles the top of a [[muffin]] spilling over its paper casing. Another slang term, "spare tire" is also used as a descriptor of the "ring" of fat surrounding one's midsection. == See also == * [[Bariatrics]] * [[Physical exercise|Exercise]] * [[General fitness training]] * [[Healthy diet]] * [[Weight loss|Intentional weight loss]] * [[Physical fitness]] * [[Obesity]] == References == {{reflist}} [[Category:Obesity]] [[Category:Medical signs]] [[Category:Medical conditions related to obesity]] [[ar:كرش]] [[de:Bierbauch]] [[nl:Bierbuik]] [[pl:Otyłość brzuszna]] [[fi:Kaljamaha]] [[sv:Ölmage]]