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Obesity
Obesity is a condition in which the natural energy reserve, stored in the fatty tissue of humans and mammals is increased to a point where it is thought to be a significant risk factor in certain health conditions, leading to increased mortality. Obesity is a condition that develops from the interaction of individual biology and the environment. Excessive body weight has been shown to correlate with various important diseases, particularly cardiovascular disease, diabetes mellitus type 2, sleep apnea, stroke, and osteoarthritis[1]. Obesity is both an individual clinical condition and, recently, a serious public health problem.
Obesity as a clinical condition is usually assessed by BMI (Body Mass Index), waist circumference, and the presence of risk factors and comorbidities[1]. In epidemiological studies BMI alone is used to define obesity.
(BMI) is currently the most widely accepted calculation of excess body fat for human beings, especially for screening purposes and to monitor effect of treatments. It also the calculation used in epidemiological or population-wide measurements of obesity.
BMI was developed by the Belgian statistician and anthropometrist Adolphe Quetelet[2]. It is calculated by dividing the subject's weight in kilograms by the square of his/her height in meters (BMI = kg / m2).
The current definitions commonly in use establish the following values, agreed in 1997 and published in 2000[3]:
A BMI less than 18.5 is underweight
A BMI of 18.5 - 24.9 is normal weight
A BMI of 25.0 - 29.9 is overweight
A BMI of 30.0 - 39.9 is obese
A BMI of 40.0 or higher is severely (or morbidly) obese
BMI is a simple and accepted method for calculating body fat [4]. BMI as an indicator of a clinical condition is used in conjunction with other clinical assessments. In a clinical setting, physicians take into account race, ethnicity, athleticism (muscularity), age, sex, and other factors which can affect the interpretation of BMI.[1] BMI is used alone as an indicator of prevalence and incidence in epidemiological analysis.
Waist circumference
BMI does not take into account differing ratios of adipose to lean tissue, nor does it distinguish between differing forms of adiposity, some of which may correlate more closely with cardiovascular risk. Increasing understanding of the biology of different forms of adipose tissue has shown that visceral or central obesity (male-type or apple-type obesity) has a much stronger correlation, particularly with cardiovascular disease, than the BMI alone[5].
The absolute waist circumference (>102 cm in men and >88 cm in women) or waist-hip ratio (>0.9 for men and >0.85 for women)[5] are both used as measures of central obesity.
Body fat measurement
An alternative way to determine obesity is to assess percent body fat. Doctors and scientists generally agree that men with more than 25 percent body fat and women with more than 30 percent body fat are obese. However, it is difficult to measure body fat precisely. The most accepted method has been to weigh a person underwater, but underwater weighing is a procedure limited to laboratories with special equipment. Two simpler methods for measuring body fat are the skinfold test, in which a pinch of skin is precisely measured to determine the thickness of the subcutaneous fat layer or bioelectrical impedance analysis, usually only carried out at specialist clinics.
Source: Wikipedia
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