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Abdominal obesity, also known as central obesity and truncal obesity, is the human condition of an excessive concentration of
visceral fat Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...
around the
stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ...
and
abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...
to such an extent that it is likely to harm its bearer's health. Abdominal
obesity Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classifi ...
has been strongly linked to
cardiovascular disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...
,
Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...
, and other
metabolic Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the ...
and
vascular disease Vascular disease is a class of diseases of the vessels of the circulatory system in the human body, body, including blood vessels – the arteries and veins, and the lymphatic vessels. Vascular disease is a subgroup of cardiovascular disease. Diso ...
s.
Visceral In a multicellular organism, an organ is a collection of Tissue (biology), tissues joined in a structural unit to serve a common function. In the biological organization, hierarchy of life, an organ lies between Tissue (biology), tissue and an o ...
fat, central abdominal fat, and
waist circumference The waist is the part of the Human abdomen, abdomen between the rib cage and Hip (anatomy), hips. Normally, it is the narrowest part of the torso. ''Waistline'' refers to the horizontal line where the waist is narrowest, or to the general appe ...
show a strong association with
type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...
. Visceral fat, also known as organ fat or ''intra-abdominal fat'', is located inside the peritoneal cavity, packed in between internal organs and
torso The torso or trunk is an anatomical terminology, anatomical term for the central part, or the core (anatomy), core, of the body (biology), body of many animals (including human beings), from which the head, neck, limb (anatomy), limbs, tail an ...
, as opposed to
subcutaneous fat The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, or superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and ...
, which is found underneath the
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...
, and intramuscular fat, which is found interspersed in
skeletal muscle Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ...
. Visceral fat is composed of several adipose depots including mesenteric, epididymal white
adipose tissue Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...
(EWAT), and perirenal fat. An excess of adipose 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. Researchers first started to focus on abdominal obesity in the 1980s when they realized it had an important connection to cardiovascular disease,
diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...
, and
dyslipidemia Dyslipidemia is a metabolic disorder characterized by abnormally high or low amounts of any or all lipids (e.g. fats, triglycerides, cholesterol, phospholipids) or lipoproteins in the blood. Dyslipidemia is a risk factor for the development of ...
. Abdominal obesity was more closely related with metabolic dysfunctions connected with cardiovascular disease than was general obesity. In the late 1980s and early 1990s insightful and powerful imaging techniques were discovered that would further help advance the understanding of the health risks associated with body fat accumulation. Techniques such as
computed tomography A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...
and
magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...
made it possible to categorize mass of adipose tissue located at the abdominal level into intra-abdominal fat and subcutaneous fat. Abdominal obesity is linked with higher cardiovascular events among South Asian ethnic populations.


Health risks


Heart disease

Abdominal obesity is typically associated with a statistically higher risk of
heart disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina pectoris, angina, myocardial infarction, heart attack), heart failure, ...
,
hypertension Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...
, insulin resistance, and
type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...
(see below). With an increase in the waist to hip ratio and overall waist circumference the risk of death increases as well.
Metabolic syndrome Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndro ...
is associated with abdominal obesity, blood lipid disorders, inflammation, insulin resistance, type 2 diabetes, and an increased risk of developing cardiovascular disease.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.
It is now generally believed that intra-abdominal fat is the depot that conveys the biggest health risk. Recent validation has concluded that total and regional body volume estimates correlate positively and significantly with biomarkers of cardiovascular risk and that BVI calculations correlate significantly with all biomarkers of cardiovascular risk.


Diabetes

There are numerous theories as to the exact cause and mechanism in
type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...
. Central obesity is known to predispose individuals for insulin resistance. Abdominal fat is especially active hormonally, secreting a group of hormones called adipokines that may possibly impair glucose tolerance. But adiponectin, an anti-inflammatory adipokine, which is found in lower concentration in obese and diabetic individuals has shown to be beneficial and protective in type 2 diabetes mellitus (T2DM). Insulin resistance is a major feature of diabetes mellitus type 2, and central obesity is correlated with both insulin resistance and T2DM itself. Increased adiposity (obesity) raises serum resistin levels, which in turn directly correlate to insulin resistance. Studies have also confirmed a direct correlation between resistin levels and T2DM. 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. Conversely, serum resistin levels have been found to ''decline'' with decreased adiposity following medical treatment.


Asthma

Developing asthma due to abdominal obesity is also a main concern. As a result of breathing at low lung volume, the muscles are tighter and the airway is narrower. Obesity causes decreased
tidal volume Tidal is the adjectival form of tide. Tidal may also refer to: * ''Tidal'' (album), a 1996 album by Fiona Apple * Tidal (king), a king involved in the Battle of the Vale of Siddim * TidalCycles TidalCycles (also known as Tidal) is a live coding ...
s due to a reduction in chest expansion that is caused both by the weight on the chest itself and the effect of abdominal obesity on flattening the diaphragm. It is commonly seen that people who are obese breathe quickly and often, while inhaling small volumes of air. People with obesity are also more likely to be hospitalized for asthma. A study has stated that 75% of patients treated for asthma in the emergency room were either overweight or obese.


Alzheimer's disease

Based on studies, it is evident that obesity has a strong association with vascular and metabolic disease which could potentially be linked to Alzheimer's disease. Recent studies have also shown an association between mid-life obesity and dementia, but the relationship between later life obesity and dementia is less clear. A study by Debette et al. (2010) examining over 700 adults found evidence to suggest higher volumes of visceral fat, regardless of overall weight, were associated with smaller brain volumes and increased risk of
dementia Dementia is a syndrome associated with many neurodegenerative diseases, characterized by a general decline in cognitive abilities that affects a person's ability to perform activities of daily living, everyday activities. This typically invo ...
. Alzheimer's disease and abdominal obesity has a strong correlation and with metabolic factors added in, the risk of developing Alzheimer's disease was even higher. Based on logistic regression analyses, it was found that obesity was associated with an almost 10-fold increase risk of Alzheimer's disease.


Other health risks

Central obesity can be a feature of lipodystrophies, a group of diseases that is either inherited, or due to secondary causes (often protease inhibitors, a group of
medication Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, treat, or preventive medicine, prevent disease. Drug therapy (pharmaco ...
s against
AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...
). Central obesity is a symptom of Cushing's syndrome and is also common in patients with
polycystic ovary syndrome Polycystic ovary syndrome, or polycystic ovarian syndrome, (PCOS) is the most common endocrine disorder in women of reproductive age. The name is a misnomer, as not all women with this condition develop cysts on their ovaries. The name origin ...
(PCOS). Central obesity is associated with glucose intolerance and
dyslipidemia Dyslipidemia is a metabolic disorder characterized by abnormally high or low amounts of any or all lipids (e.g. fats, triglycerides, cholesterol, phospholipids) or lipoproteins in the blood. Dyslipidemia is a risk factor for the development of ...
. Once dyslipidemia becomes a severe problem, an individual's abdominal cavity would generate elevated free fatty acid flux to the liver. The effect of abdominal adiposity occurs not just in those who are obese, but also affects people who are non-obese and it also contributes to insulin sensitivity. Ghroubi et al. (2007) examined whether abdominal circumference is a more reliable indicator than BMI or the presence of knee osteoarthritis in obese patients. They found that it actually appears to be a factor linked with the presence of knee pain as well as osteoarthritis in obese study subjects. Ghroubi et al. (2007) concluded that a high abdominal circumference is associated with great functional repercussion. Research published in
The Lancet ''The Lancet'' is a weekly peer-reviewed general medical journal, founded in England in 1823. It is one of the world's highest-impact academic journals and also one of the oldest medical journals still in publication. The journal publishes ...
(2023) found that high levels of visceral fat were related to poorer cognitive performance. The findings suggest that maintaining a healthy weight and metabolic health may be important for preserving cognitive function.


Causes


Diet

The currently prevalent belief is that the immediate cause of obesity is net
energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...
imbalance—the organism consumes more usable calories than it expends, wastes, or discards through elimination. Some studies indicate that visceral adiposity, together with
lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...
dysregulation and decreased insulin sensitivity, is related to the excessive consumption of
fructose Fructose (), or fruit sugar, is a Ketose, ketonic monosaccharide, simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and gal ...
. Some evidence shows that in regards to juveniles, when free fructose is present as children's fat cells mature, it makes more of these cells mature into fat cells in the abdominal region. It also caused both visceral fat and subcutaneous fat to be less sensitive to insulin. These effects were not attenuated when compared to similar
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
consumption. Intake of trans fat from industrial oils has been associated with increased abdominal obesity in men and increased weight and waist circumference in women. These associations were not attenuated when fat intake and calorie intake was accounted for. Greater
meat Meat is animal Tissue (biology), tissue, often muscle, that is eaten as food. Humans have hunted and farmed other animals for meat since prehistory. The Neolithic Revolution allowed the domestication of vertebrates, including chickens, sheep, ...
( processed meat, red meat, and
poultry Poultry () are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, Eggs as food, eggs or feathers. The practice of animal husbandry, raising poultry is known as poultry farming. These birds are most typ ...
) consumption has also been positively associated with greater weight gain, and specifically abdominal obesity, even when accounting for calories. Conversely, studies suggest that oily
fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
consumption is negatively associated with total body fat and abdominal fat distribution even when body mass remains constant. Similarly, increased soy protein consumption is correlated with lower amounts of abdominal fat in postmenopausal women even when calorie consumption is controlled. Numerous large studies have demonstrated that ultra-processed foods have a positive dose-dependent relationship with both abdominal obesity and general obesity in both men and women. Consuming a diet rich in unprocessed food and minimally processed food is linked with lower obesity risk, lower waist circumference and less chronic disease. These findings are consistent among American, Canadian, Latin American, Australian, British, French, Spaniard, Swedish, South Korean, Chinese and Sub-Saharan African populations. Obesity plays an important role in the impairment of
lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...
and
carbohydrate metabolism Carbohydrate metabolism is the whole of the biochemistry, biochemical processes responsible for the metabolic anabolism, formation, catabolism, breakdown, and interconversion of carbohydrates in life, living organisms. Carbohydrates are central t ...
shown in high-
carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...
diets. It has also been shown that quality
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
intake during a 24-hour period and the number of times the
essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms ...
threshold of approximately 10 g has been achieved is inversely related to the percentage of central abdominal fat. Quality protein uptake is defined as the ratio of essential amino acids to daily dietary protein. Visceral fat cells will release their metabolic by-products in the portal circulation, where the blood leads straight to the
liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...
. Thus, the excess of
triglyceride A triglyceride (from '' tri-'' and '' glyceride''; also TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and other vertebrates ...
s and
fatty acid In chemistry, in particular in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an ...
s created by the visceral fat cells will go into the liver and accumulate there. In the liver, most of it will be stored as fat. This concept is known as ' lipotoxicity'.


Alcohol consumption

A study has shown that
alcohol consumption Drinks containing alcohol (drug), alcohol are typically divided into three classes—beers, wines, and Distilled beverage, spirits—with alcohol content typically between 3% and 50%. Drinks with less than 0.5% are sometimes considered Non-al ...
is directly associated with waist circumference and with a higher risk of abdominal obesity in men, but not in women. After controlling for energy under-reporting, which have slightly attenuated these associations, it was observed that increasing alcohol consumption significantly increased the risk of exceeding recommended energy intakes in male participants – but not in the small number of female participants (2.13%) with elevated alcohol consumption, even after establishing a lower number of drinks per day to characterize women as consuming a high quantity of alcohol. Further research is needed to determine whether a significant relationship between alcohol consumption and abdominal obesity exists among women who consume higher amounts of alcohol. A systemic review and meta-analysis failed to find data pointing towards a dose-dependent relationship between
beer Beer is an alcoholic beverage produced by the brewing and fermentation of starches from cereal grain—most commonly malted barley, although wheat, maize (corn), rice, and oats are also used. The grain is mashed to convert starch in the ...
intake and general obesity or abdominal obesity at low or moderate intake levels (under ~500 mL/day). However, high beer intake (above ~4 L/wk) appeared to be associated with a higher degree of abdominal obesity specifically, particularly among men.


Other factors

The prevalence of abdominal obesity is increasing in Western populations, possibly due to a combination of low physical activity and high-calorie diets, and also in developing countries, where it is associated with the urbanization of populations. Other environmental factors, such as maternal smoking, estrogenic compounds in the diet, and
endocrine The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant organs. In vertebrates, the hypotha ...
-disrupting chemicals may be important also. Hypercortisolism, such as in Cushing's syndrome, also leads to central obesity. Many
prescription drug A prescription drug (also prescription medication, prescription medicine or prescription-only medication) is a pharmaceutical drug that is permitted to be dispensed only to those with a medical prescription. In contrast, over-the-counter drugs c ...
s, such as dexamethasone and other
steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...
s, can also have
side effect In medicine, a side effect is an effect of the use of a medicinal drug or other treatment, usually adverse but sometimes beneficial, that is unintended. Herbal and traditional medicines also have side effects. A drug or procedure usually use ...
s resulting in central obesity, especially in the presence of elevated insulin levels.


Diagnosis

There are various ways of measuring abdominal obesity including: *Absolute waist circumference (> in men and > in women) * Waist–hip ratio (the circumference of the waist divided by that of the hips of >0.9 for men and >0.85 for women) * Waist-stature ratio (waist circumference divided by their height, >0.5 for adults under 40 and >0.6 for adults over 50) * Sagittal Abdominal Diameter In those with a
body mass index Body mass index (BMI) is a value derived from the mass (Mass versus weight, weight) and height of a person. The BMI is defined as the human body weight, body mass divided by the square (algebra), square of the human height, body height, and is ...
(BMI) under 35, intra-abdominal body fat is related to negative health outcomes independent of total body fat. Intra-abdominal or
visceral fat Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...
has a particularly strong correlation with
cardiovascular disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...
. BMI and waist measurements are well recognized ways to characterize obesity. However, waist measurements are not as accurate as BMI measurements. Waist measurement (''e.g.'', for BFP standard) is more prone to errors than measuring height and weight (''e.g.'', for BMI standard). BMI will illustrate the best estimate of one's total body fatness, while waist measurement gives an estimate of visceral fat and risk of obesity-related disease. It is recommended to use both methods of measurements. 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 in men and 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 In healthcare, a differential diagnosis (DDx) is a method of analysis that distinguishes a particular disease or condition from others that present with similar clinical features. Differential diagnostic procedures are used by clinicians to di ...
includes distinguishing central obesity from ascites and intestinal
bloating Abdominal bloating (or simply bloating) is a short-term disease that affects the gastrointestinal tract. Bloating is generally characterized by an excess buildup of gas, air or fluids in the stomach. A person may have feelings of tightness, pressu ...
. In the cohort of 15,000 people participating in the
National Health and Nutrition Examination Survey The National Health and Nutrition Examination Survey (NHANES) is a survey research program conducted by the National Center for Health Statistics (NCHS) to assess the health and nutritional status of adults and children in the United States, and ...
(NHANES III), waist circumference explained obesity-related health risk better than BMI when
metabolic syndrome Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndro ...
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. Another measure of central obesity which has shown superiority to BMI in predicting cardiovascular disease risk is the Index of Central Obesity (waist-to-height ratio, WHtR), where a ratio of >=0.5 (i.e. a waist circumference at least half of the individual's height) is predictive of increased risk. Another diagnosis of obesity is the analysis of intra-abdominal fat having the most risk to one's personal health. The increased amount of fat in this region relates to the higher levels of plasma lipid and lipoproteins as per studies mentioned by Eric Poehlman (1998) review. 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. The effect of abdominal adiposity occurs not just in those who are obese, but also affects people who are non-obese and it also contributes to insulin sensitivity.


Index of central obesity

Index of Central Obesity (ICO) is the ratio of waist circumference and height first proposed by a Parikh ''et al.'' in 2007 as a better substitute to the widely used waist circumference in defining
metabolic syndrome Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndro ...
. The National Cholesterol Education Program Adult Treatment Panel III suggested cutoff of and for males and females as a marker of central obesity. The same was used in defining
metabolic syndrome Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndro ...
. Misra et al. suggested that these cutoffs are not applicable among Indians and the cutoffs be lowered to and for males and females. Various race specific cutoffs were suggested by different groups. The International Diabetes Federation defined central obesity based on these various race and gender specific cutoffs. The other limitation of waist circumference is that it the measurement procedure has not been standardized and in children there are no, or few, comparison standards or reference data. Parikh et al. looked at the average heights of various races and suggested that by using ICO various race- and gender-specific cutoffs of waist circumference can be discarded. An ICO cutoff of 0.53 was suggested as a criterion to define central obesity. Parikh ''et al.'' further tested a modified definition of
metabolic syndrome Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndro ...
in which waist circumference was replaced with ICO in the
National Health and Nutrition Examination Survey The National Health and Nutrition Examination Survey (NHANES) is a survey research program conducted by the National Center for Health Statistics (NCHS) to assess the health and nutritional status of adults and children in the United States, and ...
(NHANES) database and found the modified definition to be more specific and sensitive. This parameter has been used in the study of
metabolic syndrome Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndro ...
and
cardiovascular disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...
. Central obesity in individuals with normal BMI is referred to as normal weight obesity.


Sex differences

There are sex-dependent differences in regional fat distribution. Males are more susceptible to upper-body fat accumulation, most likely in the belly, due to sex hormone differences. When comparing the body fat of men and women it is seen that men have close to twice the visceral fat as that of pre-menopausal women. In women,
estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...
is believed to cause fat to be stored in the
buttocks The buttocks (: buttock) are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region. In humans, the buttocks are located between the lower back and the perineum. They are composed of a lay ...
, thighs, and
hips In vertebrate anatomy, the hip, or coxaLatin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) (: ''coxae'') in medical terminology, refers to either an anatomical region or a joint ...
. When women reach
menopause Menopause, also known as the climacteric, is the time when Menstruation, menstrual periods permanently stop, marking the end of the Human reproduction, reproductive stage for the female human. It typically occurs between the ages of 45 and 5 ...
and the estrogen produced by
ovaries The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...
declines, fat at their buttocks, hips, and thighs decreases while fat at their belly increases. 50% of men and 70% of women in the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
between the ages of 50 and 79 years now exceed the waist circumference threshold for central obesity. Central obesity is positively associated with coronary heart disease risk in women and men. It has been hypothesized that the sex differences in fat distribution may explain the sex difference in coronary heart disease risk. Even with the differences, at any given level of central obesity measured as waist circumference or waist to hip ratio, coronary artery disease rates are identical in men and women.


Management

A permanent routine of exercise, eating healthily, and, during periods of being overweight, consuming the same number or fewer calories than used will prevent and help fight obesity. A single pound of fat yields approximately 3500 calories of energy (32 000 kJ energy per kilogram of fat), and weight loss is achieved by reducing energy intake, or increasing energy expenditure, thus achieving a negative balance. Adjunctive therapies which may be prescribed by a physician are orlistat or sibutramine, although the latter has been associated with increased cardiovascular events and strokes and has been withdrawn from the market in the US, the UK, the EU,
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
,
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
,
Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...
, and
Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
. A 2006 study published in the '' International Journal of Sport Nutrition and Exercise Metabolism'' suggests that combining cardiovascular (aerobic) exercise with resistance training is more effective than cardiovascular training alone in getting rid of abdominal fat. An additional benefit to exercising is that it reduces stress and insulin levels, which reduce the presence of
cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...
, a hormone that leads to more belly fat deposits and leptin resistance. Self-motivation by understanding the risks associated with abdominal obesity is widely regarded as being far more important than worries about cosmetics. In addition, understanding the health issues linked with abdominal obesity can help in the self-motivation process of losing the abdominal fat. As mentioned above, abdominal fat is linked with cardiovascular disease, diabetes, and cancer. Specifically it is the deepest layer of belly fat (the fat that cannot be seen or grabbed) that poses health risks, as these "visceral" fat cells produce hormones that can affect health (e.g. increased insulin resistance and/or breast cancer risk). The risk increases considering the fact that they are located in the proximity or in between organs in the abdominal cavity. For example, fat next to the liver drains into it, causing a fatty liver, which is a risk factor for insulin resistance, setting the stage for type 2 diabetes. However, visceral fat is more responsive to the circulation of catecholamines. In the presence of
type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...
, the physician might instead prescribe metformin and thiazolidinediones ( rosiglitazone or pioglitazone) as
antidiabetic drug Drugs used in diabetes treat types of diabetes mellitus by decreasing blood sugar level, glucose levels in the blood. With the exception of Insulin (medication), insulin, most GLP-1 receptor agonists (liraglutide, exenatide, and others), and pra ...
s rather than
sulfonylurea Sulfonylureas or sulphonylureas are a class of organic compounds used in medicine and agriculture. The functional group consists of a sulfonyl group (-S(=O)2) with its sulphur atom bonded to a nitrogen atom of a ureylene group (N,N-dehydrourea ...
derivatives. Thiazolidinediones may cause slight weight gain but decrease "pathologic" abdominal fat (visceral fat), and therefore may be prescribed for diabetics with central obesity. Thiazolidinedione has been associated with heart failure and increased cardiovascular risk; so it has been withdrawn from the market in Europe by EMA in 2010. Low-fat diets may not be an effective long-term intervention for obesity: as Bacon and Aphramor wrote, "The majority of individuals regain virtually all of the weight that was lost during treatment." The Women's Health Initiative ("the largest and longest randomized, controlled dietary intervention clinical trial") found that long-term dietary intervention increased the waist circumference of both the intervention group and the control group, though the increase was smaller for the intervention group. The conclusion was that mean weight decreased significantly in the intervention group from baseline to year 1 by 2.2 kg (P<.001) and was 2.2 kg less than the control group change from baseline at year 1. This difference from baseline between control and intervention groups diminished over time, but a significant difference in weight was maintained through year 9, the end of the study.


Society and culture


Myths

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, if any, on fat in that area of the body, or on the body's distribution of body fat. The same logic applies to sit-ups and belly fat. Sit-ups, crunches and other abdominal exercises are useful in building the abdominal muscles, but they have little effect, if any, on the
adipose tissue Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...
located there.


Colloquialisms

A large central adiposity deposit has been assigned many common use names, including "spare tire", "love handle", "paunch", "boiler", and "potbelly". Several colloquial terms used to refer to central obesity, and to people who have it, refer to
beer Beer is an alcoholic beverage produced by the brewing and fermentation of starches from cereal grain—most commonly malted barley, although wheat, maize (corn), rice, and oats are also used. The grain is mashed to convert starch in the ...
drinking. However, there is little scientific evidence that beer drinkers are more prone to central obesity, despite its being known colloquially as "beer belly", "beer gut", or "beer pot". One of the few studies conducted on the subject did not find that beer drinkers are more prone to central obesity than nondrinkers or drinkers of wine or spirits. Chronic alcoholism can lead to
cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, chronic liver failure or chronic hepatic failure and end-stage liver disease, is a chronic condition of the liver in which the normal functioning tissue, or parenchyma, is replaced ...
, symptoms of which include gynecomastia (enlarged breasts) and ascites (abdominal fluid). These symptoms can suggest the appearance of central obesity.


Economics

Researchers in Copenhagen examined the relationship between waist circumferences and costs among 31,840 subjects aged 50–64 years of age with different waist circumferences. Their study showed that an increase in just an additional centimetre above normal waistline caused a 1.25% and 2.08% rise in health care costs in women and men respectively. To put this in perspective, a woman with a waistline of 95 cm (approx 37.4 in) and without underlying health problems or co-morbidities can incur economic costs that are 22%, or US$397, higher per year than a woman with a normal waist circumference."Economic costs of abdominal obesity"; Højgaard, Betina and Olsen, Kim Rose and Søgaard, Jes and Sørensen, Thorkild I A and Gyrd-Hansen, Dorte; ''Obesity facts'', , 2008, Volume 1, Issue 3, pp. 146–154.


See also

* Bariatrics, the branch of medicine that deals with the causes, prevention, and treatment of obesity *
Lipoatrophy Lipoatrophy is the term describing the localized loss of fat tissue. This may occur as a result of subcutaneous injections of insulin in the treatment of diabetes, from the use of human growth hormone or from subcutaneous injections of copaxone u ...
, the term describing the localized loss of fat tissue * Muffin top * Normal weight obesity, normal BMI with excessive fat, usually centrally localized *
Panniculus The panniculus (often incorrectly referred to as pannus) is a dense layer of fatty tissue consisting of excess subcutaneous fat within the lower abdominal region. Panniculi can form after rapid weight loss, as seen with strict exercise plans—i ...
, hanging belly fat * Steatosis, also called ''fatty change'', ''fatty degeneration'' or ''adipose degeneration''


References


Further reading

* * *


External links

* {{DEFAULTSORT:Abdominal Obesity Abdomen Medical conditions related to obesity Medical signs Classification of obesity Tissues (biology)