Causes and Prevention of Obesity

Dr Shihaan — Fri, 31 Oct 2008 08:04:20 +0000

Epidemiology/Causes:

a) Age: Obesity can occur at all ages. The incidence of obesity increases with age. Obese infants are more likely to be obese in later life.

One-third of obesity in adults has been life long, ie since infancy.

Most adipose cells are formed in early life, therefore infants who have more of these cells (hyperplastic obesity) are more likely to be obese in infancy and later life. It is very difficult to treat hyperplastic obesity in adult life.

b) Genetic Factors: There are genetic factors that could explain the aetiology of obesity. There is a close relationship in the weight of identical twins, even if they are brought up in different environments.

c) Familial Tendency: It is well known that obesity runs in families. It is very difficult to determine if familial obesity is due to genetic factors, because members of the same family have similar eating habits.

d) Sex: Men are more likely to be obese at a relatively young age (between 29 and 35 years) while women gain most weight between 45 and 49 years of age.

e) Physical inactivity: There is an increased incidence of obesity among people who are physically inactive (Company executives) .This is a vicious cycle,ie the increase in obesity causes reduction in physical activity which in turn increases obesity.

f) Endocrine factors: This provides the explanation of obesity in Cushing’s syndrome and growth hormone deficiency. Endocrine factors are probably not involved in obesity in normal ndividuals.

g) Socio-economic status: There is an inverse relationship between obesity and socio-economic status.

h) Eating habits: This is very important. Eating in-between meals and preference to fats, refined foods and sweets can easily cause obesity.

Prevention of Obesity:

Prevention of obesity should begin in early childhood. Children should be taught about healthy eating habits.

Individuals at risk of obesity should be told to eat diets low in fat and high in fiber (like roots, cereals, legumes, fruits and vegetables). They should also avoid sedentary lifestyle and take regular exercise.

Control of Obesity:

i) Weight reduction by dietary changes: Dietary changes include an increase in high fiber foods (Please see above-as discussed in prevention of obesity). It is unfortunate that attempts in reduction in weight by dietary advice is usually unsuccessful.

ii) Increased physical activity: Regular physical activity can help reduce obesity, for effective reduction of weight this must be combined with dietary advice.

iii) Severe Obesity: In severe obesity surgery may be beneficial in some patients (eg Gastric bypass, gastroplasty etc).

References:

Short Textbook of Public Health Medicine for the Tropics- Adetokunbo O. Lucas and Herbert M. Gilles-4th edition.

Obesity and Pregnancy -Chapter 33 by Rani Akhil Bhat .Medical Disorders in Pregnancy- An Update .edited by Hiralal Konar and Pralhad Kushtagi. Federation of Obstetric and Gynaecological Societies of India.First Edition.

WHO 2000 No. 894

WHO 1995 No 854

FAO/WHO/UNU 1985 No. 724- Energy and protein requirements.

Chapter 6 Epidemiology of Non- Communicable diseases -Park’s Textbook of Preventive and Social Medicine by K Park.

Obesity- an introduction

Dr Shihaan — Fri, 31 Oct 2008 02:12:02 +0000

Obesity is on the rise throughout the world. Even though the developed countries are affected more than the developing countries, the developing countries are catching up very fast.

Obesity is a major cause of morbidity and mortality. The rise in the incidence of obesity is unfortunate, because it is preventable.

Numerous complications have been linked to obesity, some examples are increased risk of cesarean delivery, gestational diabetes, gestational hypertension, complications of anaesthesia and post-operative wound infections.

Maternal obesity also increases the risk of fetal mortality and morbidity. It is also thought that maternal obesity could increase the risk of nural tube defects.

Definition of Obesity:

Obesity may be defined as an abnormal growth of the adipose tissue due to an enlargement of fat cell size( hypertrophic obesity) or an increase in fat cell number (hyperplastic obesity) or a combination of both.

Various methods have been used to define and classify obesity.

At the moment modern medicine accepts the Quetelet index for the definition and classification of obesity. The Quetelet index is weight/(height x height) . Weight in kilogram’s and height in meters. The quetelet index gives the body mass index( BMI).

Obesity is labeled when the BMI is >30 Kg/m sq

Who Grading of Body Mass Index (BMI)

BMI < 16 indicates grade 3 thinness

BMI 16.0-16.99 indicates grade 2 thinness

BMI 17.0-18.49 indicates grade 1 thinness

BMI 18.5-24.99 is the normal range for an individual

BMI < 25.0-29.99 indicates grade 1 overweight

BMI < 30.0-39.99 indicates grade 2 overweight

BMI > 40.00 indicates grade 3 overweight

Freedman’s classification of BMI

Class I ( BMI 30-34.9 Kg/m sq )

Class II (BMI 35 -39.9Kg/ m sq)

Class III (BMI >40 Kg/ m sq)

Incidence of Obesity

Obesity is a pandemic. It is a public health problem. There has been an increase of 75 percent of obese adults over the last two decades. Obesity now affects schoolchildren as well as all groups of adults including pregnant women. 15% of children (6 to 11 years of age) and 21% of adolescents (12 to 19 years of age) are now overweight.

Approximately 300,000 adults die each year from obesity related cause. Women who are obese have a two fold increase risk of heart failure and mortality risk from cardiovascular disease. The incidence of cardiovascular diseases also increases with increasing BMI. Obesity is perhaps the most prevalent form of malnutrition.

Criteria used to assess obesity:

1)Body Weight

It is conventional to accept +2 SD (standard deviations) from the median weight for height as a cut off point for obesity.

a) Body Mass Index (Quetelet Index)

= Weight(Kg)/ height x height(m)

b) Ponderal Index

=Height (cm)/ cube root of body weight (Kg)

c)Broca Index

=Height (cm) minus 100 eg if a person’s height is 155cm his ideal weight is (155-100)=55Kg.

d)Lorentz’s formula

Ht (cm)-100 – { Ht (cm)-150/2 (women) or 4 (men)

e) Corpulence Index

=Actual weight/ Desirable weight

This should not exceed 1.2

2) Waist Circumference and Waist : Hip Ratio (WHR)

This is very important because it does not take into consideration the height of an individual , but it still relates closely to the BMR WHR.

This tries to estimate the intra-abdominal fat mass and total body fat.

The waist circumference is measured at the mid-point at the lower border of the rib cage and the iliac crest.

It is now established that that a high WHR (>1.0 in men and >0.85 in women) indicates abdominal fat accumulation.

3) Skin Fold Thickness

This index is not popular any more because it is difficult to repeat and get the same result in the same individual.

This method takes into consideration that a large proportion of total body fat is located just under the skin.

Different types of calipers are used for this purpose (eg Harpenden Skin Callipers).

Measurements are taken at all four sites- ie mid-triceps, biceps, subscapular and suprailiac regions. The sum of the measurements should be less than 40mm in boys and 50 mm in girls.