Monday, November 8, 2010
Abdominal obesity,colloquially known as belly fat or clinically as central obesity,is the accumulation of abdominal fat resulting in an increase in waist size.There is a strong correlation between central obesity and cardiovascular disease. Visceral fat,also known as organ fat or intro-abdominal fat,is located inside the peritoneal cavity,packed in between internal organs and torso,as opposed to subcutaneous fat which is found underneath the skin,and intramuscular fat which is found interspersed in skeletal muscle.Visceral fat is composed of several adipose depots including including mesenteric,epididymal white adipose tissue(EWAT)and perirenal fat.An excess of visceral fat is known as central obesity,the "pot belly"or "beer belly" effect,in which the abdomen protrudes excessively.This body type is also known as "apple shaped",as opposed to "pear shaped",in which fat is deposited on the hips and buttocks.Causes-The immediate cause of obesity is net energy imbalance-the organism consumes more usable calories than it expends,wastes,or discards via elimination.The specific cause of central distribution of fat is also not well understood .In humans,central obesity is correlated with overeating and a sedentary lifestyle.Hypercortisolism,such as in Cushing's syndrome also leads to central obesity.Many prescription drugs can also have side effects resulting in obesity .Because fat in the midsection,specifically in fat cells deposits deep in the abdomen. Diagnosis-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(>102 centimetres(40in) in men and >88 centimetres(35in) in women)and the waist-hip ratio(>0.9 for men and >0.85 for women) are both used as measures of central obesity.A differential diagnosis includes distinguishing central obesity from ascites and intestinal bloating.In the cohort of 15,000 people participating in the National Health and Nutrition Examination Survey,waist circumference explained obesity-related health risk better than the body mass index(or BMI) when metabolic syndrome was taken as an outcome measure and this difference was statistically significant.In other words,excessive waist circumference appears to be more of a risk factor for metabolic syndrome than BMI. An increasing acceptance of the importance of central obesity within the medical profession as an indicator of health risk has led to new developments in obesity diagnosis such as the Body Volume Index,which measures central obesity by measuring a person's body shape and their weight distribution.BVI is based upon the principle that excess abdominal weight,measured by part volume,constitutes a greater health risk.Recent validation has concluded that total and regional body volume estimates correlate positively and significantly with all biomarkers of cardio-vascular risk. Health risks-Central obesity is associated with a statistically higher risk of heart disease,hypertension,insulin resistance,and Diabetes Mellitus Type2.Belly fat is a symptom of metabolic syndrome,and is an indicator used in the diagnosis of that disorder. Central obesity can be a feature of lipodystrophies,a group of diseases which is either inherited,or due to secondary causes(often protease inhibitors,a group of medication against AIDS).Central obesity is a symptom of Cushing's syndrome and is also common in patients with polycystic ovary syndrome(PCOS).Central obesity is associated with glucose intolerance and dyslipidemia.