 Basic Facts On Obesity General Definition of Obesity Obesity is generally defined as the abnormal and excessive accumulation of fat in adipose tissue in the human body. The level of fat accumulation is to such a high extent that health may be impaired or affected. Obesity is now recognized as a risk factor for the development of diabetes, gallbladder disease, cardiovascular disease, hypertension, sleep apnea, osteoarthritis, and some forms of cancer. In fact, it is now known as one of the major causes of serious health problems for people in the western world. This has only occurred over the last few decades but it has affected thousands of people. Since the major cause of death in the United States and most European countries is cardiovascular disease, any approach for combatting obesity should be designed to reduce the risks of this problem. Over the last two to three decades, over eating and obesity have been gone from being relatively minor public health issues (that primarily affect the most affluent societies) to a major threat to public health that is being increasingly seen throughout the world. The plight of the most affected obese populations, like the UK, has been well publicized. However, less documented have been increases in population obesity in a different place in the world that are now increasingly being monitored. Adipose Cells and Measurements Obesity is a disease whose pathology lies in the increased size and number of fat cells. Ananatomic classification of obesity from which a pathologic classification arises is based on the number of adipocytes,on the regional distribution of body fat, or on the characteristics of localized fat deposits. To measure the level and stages of adipose tissue and then to determine its likelihood of affecting health is not an easy task. Quantification of adipose tissue mass can be achieved by a number of laboratory methods including underwater body density measurement and body fat content estimated by the dualenergy X- ray Absorptiometer. In addition, the development of new techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT), has provided researchers with opportunities to describe human adiposity in more detail. However, most of these methods require costly equipment meaning that their use is limited to clinical research setting. In large-scale population surveys and clinical/public health screening, an index of body weight adjusted for stature is commonly used as a surrogate for body fat content. These indices are defined as different combinations of weight and height, such as weight divided by height or are defined as weight expressed as a percentage of mean weight for a given height and sex. Body Mass Index (BMI) The most widely used is Quetelet’s index, better known as body mass index (BMI), which is body weight (kg) divided by height squared (m2). This index has been shown to correlate weakly with height and strongly with body fatness in adults. Although the correlation between BMI and body fat adjusted for height is high (r_ 0.82–0.91) in adults [8], BMI fails to distinguish between lean body mass and fat. Thus, the relationship between BMI and body fatness varies according to body composition and proportions. For instance, the percentage of body fat mass is higher in females than in males with a similar BMI. Physiological Differences In addition, body fatness has been shown to vary by age both before adulthood and with ageing. Any agerelated change in height has an influence on BMI as well. Determining the weight status and level of adiposity in children and adolescents is even more problematical. This is a stage of rapid growth and development. During growth in childhood and adolescence, not only does height increase but body composition changes as well, thus classification of obesity according to a single measure is difficult. In addition, international or regional weight status standards for children and adolescents may be less reliable as the age of onset of puberty and its associated physical changes often varies between different countries, ethnic groups or cultures. Continues... | 
No comments:
Post a Comment