Assessment of Obesity
| Obesity And Its Evolution To Diabetes - Dr. Sunil Gupta, Diabetes Care Centre, Nagpur, |
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| Introduction Human and many other animals, possess a metabolism that is geared towards storage of energy – as fat – at every possible opportunity. Unfortunately, in modern, affluent societies, where food is rarely lacking and physical exertion often unnecessary, this can lead to an excessive accumulation of fat and individuals become overweight or obese. The problem is particularly striking in some ethnic groups when they are introduced to a “Western “ life style with a diet containing convenience foods that are rich in fats and sugars and high in calories. Obesity causes a large number of distressing symptoms and is associated with increased morbidity and reduced life expectancy. The burden or excess weight puts strain on muscles and joints, causing arthritis and respiratory problem. Obesity disturbs normal homoeostatic mechanisms, precipitating the development of impaired glucose tolerance (IGT), Type 2 (non-insulin-dependent) diabetes and cardiovascular disease (CVD) in predisposed individuals. Definitions and criteria The most commonly used system for assessing fat is the Quetelet’s Index. |
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| Obesity is associated with excess mortality. The mortality rates rise more sharply when BMI is between 27 kg/m2 and 40 kg/m2. However, the proportion of adults with a low BMI is small in Western societies and their exaggerated mortality is largely related to smoking. The World Health Organisation (WHO) has adopted a BMI > 30 kg/m2 to pose the greatest risk of health. Recently, the waist circumference has been increasingly adopted for health promotion and epidemiological purposes, because waist measurement reflects both overall fatness and also central fat accumulation. A waist measurement of 80 cm (women) or 94 cm (men) corresponds with a BMI of 25 kg/m2. A waist measurement of > 88 cm (women) or 102 cm (men) corresponds with a BMI of 30 kg/m2 and indicates a high risk of CVD and diabetes.
Obesity and diabetes A number of prospective and prevalence studies have shown obesity to be related to an increase in the incidence of Type 2 diabetes. One recent study, which followed more than 50,000 men for 5 years showed that as BMI increased above the threshold of 24 kg/m2 there was an exponential rise in the risk of developing Type 2 diabetes. Men with a BMI > 35 kg/m2 were over 40 times more likely to develop Type 2 diabetes, compared with those with a BMI < 23 kg/m2. The WHO cities increased adiposity as the single most important risk factor for the development of Type 2 diabetes. Importance of weight gain Weight gain, in addition to BMI, is also a strong risk factor for diabetes. For example, in the Health professionals |
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| Follow-up study, after controlling for BMI at entry, family history, age and smoking, men who gained > 13.6 kg over the 5 years of the study had a risk 4.5 times greater than that of men who remained within 4.5 kg of their weight at entry. Across the range of BMI, absolute weight gain was positively associated with the risk of diabetes.
Duration of obesity The longer a person remains obese, the higher their risk of developing Type 2 diabetes. In one study, people who had been at a BMI of > 30 for more that 10 years had over twice the risk of Type 2 diabetes compared with those who had been obese for less than 5 years. |
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