OBESITY AND OVERWEIGHT

Obesity is a chronic, complex, multifactorial disorder with increasing prevalence in modern society. It is an epidemic disease that threatens to inundate health care resources by increasing the incidence of diabetes, heart disease, hypertension, and cancer. Mortality risk increases in direct proportion to excess weight. Obesity is the world's 2nd most important risk for premature mortality (after smoking). Even slight overweight increases morbidity & mortality by inducing risk factors for metabolic disorders.

Overweight and obesity are some of the biggest challenges facing modern medicine today. Obesity is both an individual clinical condition and is increasingly viewed as a serious public health problem. It is clearly recognized that obesity is reaching epidemic proportions in all segments of our society. Among older adults, the rate of obesity has risen dramatically over the past 20 years. Certainly, it is common in wealthier countries it affects 1 in 3 people, and even in developing economies, rates in some areas exceed 1 in 5.

It is now estimated that approximately 40% of individuals between the ages of 60 and 69 (42.5% of women and 38.1% of men) have a body mass index of 30 or more (i.e., they are clinically obese). Thirty percent of those between the ages of 70 and 79 are obese (31.9% women and 28.9% men).

Definition and Classification

Definition:

Obesity is a chronic disease like hypertension and atherosclerosis. Like other chronic disease obesity requires lifestyle modification and long-term management. Obesity is a risk factor for a wide range of diseases and is associated with a considerable number of co-morbid conditions. The correlation between obesity and coronary artery disease, hypertension, lipid disorders and type 2 diabetes is well documented.

The obesity is an imbalance between the energy ingested in food and the energy expended. The excess energy is stored in fat cells that enlarge and/or increase in number. It is this hyperplasia and hypertrophy of fat cells that is the pathological lesion of obesity. Enlarged fat cells produce the clinical problems associated with obesity either because of either the weight or mass of the extra fat or because of the increased secretion of free fatty acids and numerous peptides from enlarged fat cells. The consequence of these two mechanisms is other diseases, such as diabetes mellitus, gallbladder disease, osteoarthritis, heart disease, and some forms of cancer. The spectrum of medical, social, and psychological disabilities includes a range of medical and behavioral problems

Classification:

Obesity is defined as an excess of body fat. Dependent on the degree, this pathological condition is classified as 'overweight' or 'obesity'.

Obesity results when the size or number of fat cells in a person's body increases. A normal-sized person has between 30 and 35 billion fat cells. When a person gains weight, these fat cells first increase in size and later in number. Body Mass Index is a simple index of weight-for-height that is commonly used in classifying overweight and obesity in adult populations and individuals.

Body Mass Index (BMI)

Body Mass Index or BMI is one of the most widely accepted means of assessing obesity Body Mass Index (or sometimes called the Quetelet Index) is a statistical measure of the weight of a person scaled according to height. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing "social physics".

It is calculated as follows.

BMI provides the most useful population-level measure of overweight and obesity, as it is the same for both sexes and for all ages of adults. However, it should be considered as a rough guide because it may not correspond to the same degree of fatness in different individuals.

Additional risks:

• Large waist circumference (men>40 in; women >35 in)
• 5 kg or more weight gain since age 18-20 y
• Poor aerobic fitness

WAIST AND HIP MEASUREMENTS

Waist and hip measurements are useful for defining body fat distribution, which is of special value when assessing health risks. The fat distribution around the waist is known as apple-shaped obesity or android distribution. The fat distribution around the buttocks and thighs is known as pear-shaped obesity or gynoid distribution. Apple-shaped obesity (android fat distribution) has a higher cardiovascular risk of morbidity and mortality than the pear-shaped obesity (gynoid type).

Fat distribution should be determined predominantly in patients with only moderate overweight, as this is not taken into account by the BMI.

Two important measurements:

• Waist Circumference
• Waist to Hip Ratio (WHR)

Waist circumference is the simplest method for identifying the need for weight management and is an indicator of visceral obesity. Waist circumference has been identified as a simple predictor of health risks.

Waist-hip ratio or Waist-to-hip ratio (WHR) is the ratio of the circumference of the waist to that of the hips. It measures the proportion by which fat is distributed around the torso. The concept and significance of WHR was first theorized by evolutionary psychologist Dr. Devendra Singh at the University of Texas at Austin in 1993.

The waist is measured between the coastal arch and iliac crest, the hip circumference at the level of the trochanter major. (i.e., measure the waist at its narrowest point width-wise, usually just above the belly button. Measure the hips around the widest part of the hip bones).

WHR has proven useful in daily practice. Then divide the waist measurement by the hip measurement.

A ratio of 1.0 or grater in men, and grater
than 0.85 in women is particularly associated
with metabolic complications.

FACTS ABOUT OVERWEIGHT AND OBESITY

Once considered a problem only in high-income countries, overweight and obesity are now dramatically on the rise in low- and middle-income countries, particularly in urban settings

OBESITY: The extent of the problem

• Globally, an estimated >1.6 billion adults (age 15+) are overweight & at least 400 million of them are classified as obese.
• Current obesity levels range from below 5% in China , Japan and certain African nations, to over 75% in urban Samoa . But even in relatively low prevalence countries like China , rates are almost 20% in some cities.
• An estimated 22 million children under five are estimated to be overweight worldwide.
• The problem is global and increasingly extends into the developing world; for example, in Thailand the prevalence of obesity in 5-to-12 year olds children rose from12.2% to 15-6% in just two years.
• WHO further projects that by 2015, approximately 2.3 billion adults will be overweight and more than 700 million will be obese.

Many low- and middle-income countries are now facing a "double burden" of disease:

• While they continue to deal with the problems of infectious disease and under-nutrition, at the same time they are experiencing a rapid upsurge in chronic disease risk factors such as obesity and overweight, particularly in urban settings.

It is not uncommon to find under-nutrition and obesity existing side-by-side within the same country, the same community and even within the same household. This double burden is caused by inadequate pre-natal, infant and young child nutrition followed by exposure to high-fat, energy-dense, micronutrient-poor foods and lack of physical activity

Obesity in India

Even in countries like India , which are typically known for high prevalence of under nutrition, significant proportions of overweight and obese now coexist with the undernourished.

India is facing an obesity crisis among its newly wealthy middle class as millions of its rural poor still struggle for enough to eat. As the country becomes richer, many people are becoming fatter and are seeking medical help. Seventy-six percent of women in the capital, New Delhi , are suffering from abdominal obesity, according to a survey by the All-India Institute of Medical Sciences.

Although Indian food was always high in calories, families now spend more than ever on eating out and buying processed food, according to the survey. Over the last few years there has been an extremely rapid change in diet - not just in Delhi and Mumbai, but in smaller towns, too, People are snacking in a new way. Many children no longer take lunch-boxes to school. They drink cola and eat burgers. There is no awareness among parents that this is a problem as said by the co-author of the study.

Prevalence of obesity and over weight in India is shown below.

Prevalence of Obesity and overweight in India

Cross-sectional surveys were conducted in six-twelve urban streets in each of five cities from various regions of India . This study, was conducted in five Indian cities namely Moradabad (n=902), Trivandrum (n=760), Calcutta (n=410), Nagpur (n=405), Bombay (n=780) cities. Total number of subjects involved in the study was 3257. The age group of subjects was in the range between 25 and 64 years. All Subje