The document discusses obesity as a chronic disease characterized by abnormal fat tissue growth, measured by body mass index (BMI), and affecting various demographics globally. It outlines the epidemiological determinants of obesity including age, sex, genetic factors, physical inactivity, and socio-economic status, alongside methods for obesity assessment such as skin fold thickness and waist-hip ratio. The document concludes with the hazards of obesity, including increased morbidity and mortality, and methods for prevention and control through dietary changes, physical activity, and surgical treatments.

1. OBESITY
Dr Rajesh Kumar Ludam
P.G Student, Dept of Community
Medicine

2. INTRODUCTION
 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 (hyperplasic obesity)or a combination of
both.
 Expressed in terms of body mass index (BMI).
 weight gain affects the risk associated with obesity,
and the kind of disease that results.
 As a chronic disease, prevalent in both developed
and developing countries, and affecting children(10-
20%) as well as adults(20-40%).
 The most prevalent form of malnutrition.

3.  Epidemiological
determinants-:
- Age
- Sex
- Genetic Factor
- Physical Inactivity
- Socio-economic Status
- Eating Habits
- Psychological Factors
- Familial Tendency
- Endocrine Factors
- Alcohol & Smoking
- Education
- Ethnicity
- Drugs

4. A)Age-: Obesity can occur at any age, and generally
increases with age. Infants with excessive weight
gain have an increased incidence of obesity in later
life.
- most adipose cells are formed early in life.
B) SEX-: Women generally have higher rate of obesity
than men, although men may have higher rates of
overweight.
- In the Framingham, USA study, men were found to
gain most weight between the ages of 29 and 35
years, while women gain most between 45 and 49
gears of age.
- Woman's BMI increases with successive
pregnancies with a wt gain of 1 kg per pregnancy

5. C)Genetic Factors-: Twin studies have shown a close
correlation between the weights of identical twins even
when they are reared in dissimilar environments.
- Recent studies have shown that the amount of
abdominal fat was influenced by a genetic component
accounting for 50-60 per cent of the individual
differences.
D)Physical Inactivity-: Physical activity and physical fitness
are important modifiers of mortality and morbidity related
to overweight and obesity.
- Physical inactivity may cause obesity, which in turn
restricts activity. This is a vicious circle.
- Sedentary lifestyle particularly sedentary occupation and
inactive recreation such as watching television promote
it.

6. E)Socio-economic Status-: There is a clear inverse
relationship between socio-economic status and obesity.
- Within some affluent countries, however, obesity has
been found to be more prevalent in the lower socio-
economic groups.
F)Eating Habits-: The composition of the diet, the
periodicity with which it is eaten and the amount of
energy derived from it are all relevant to the aetiology of
obesity.
- A diet containing more energy than needed may lead to
prolonged post-prandial hyperlipidaemia and to
deposition of triglycerides in the adipose tissue resulting
in obesity
- heavy advertisement of fast food outlets of energy-
dense, micronutrient poor food and beverages is
disturbing our eating habits.

7. G) Psychosocial Factors -: Psychosocial factors (e.g. emotional
disturbances) are deeply involved in the aetiology of obesity.
- Overeating may be a symptom of depression, anxiety,
frustration and loneliness in childhood as in the adult life.
H)Familial Tendency : Obesity frequently runs in family(obese
parents frequently having obese children), but not
necessarily explained solely by the influence of genes.
I)Endocrine Factors-: These may be involved in occasional
cases. e.g. Cushing's syndrome, growth hormone deficiency.
J)Alcohol-: A recent review of studies concluded the
relationship between alcohol consumption and adiposity
generally positive for men and negative for women.

8. K)Education-: In most affluent societies. there is an relationship
between educational level and prevalence of overweight .
L)Smoking-: In most populations, smokers weigh somewhat
less than ex-smokers: individuals who have never smoked
fall somewhat between the two.
M)Ethnicity-: Ethnic groups in many industrialized specially
appear to be especially susceptible to the development of
obesity and its complications.
- Evidence suggest that this may be due to a genetic
predisposition to obesity that only becomes apparent when
such groups are exposed to a more affluent life style
N)Drugs-: Use of certain
drugs,e.g.corticosteroids,contraceptives. insulin, p-adrenergic
blockers, etc. can cause weight gain.

9. Use of BMI to Classify Obesity
 Body mass index (BMI) is a simple index of weight-
for-height that is commonly used to classify
underweight, over weight and obesity in adults.
 It is defined as the weight in Kilograms divided by
the square of the height in metres (kg/m²).
 example, an adult who weighs 70 kg and whose
height is 1.75 mtr will have a BMI of 22.9
BMI= 70 (kg)/17.75²(m²) =22.9
 The WHO classification is based primarily on the
association between BMI and mortality.

11.  These BMI values are age-independent and the same
for both sexes.
 The risks associated with increasing BMI are continuous
and graded and begin at a BMI above 25.
 BMI does not distinguish between weight associated
with muscle and weight associated with fat.
 In addition, the percentage of body fat mass increases
with age up to 60-65 years in both sexes. and is higher
in women than in men of equivalent BMl.

12. ASSESSMENT OF OBESITY
 Body composition are as under-:
a. the active mass (muscle, liver, heart etc.)
b. the fatty mass (fat)
c. the extracellular fluid (blood, lymph, etc.)
d. the connective tissue (skin. bones. Connective
 The most widely used criteria are :
1. BODY WEIGHT
2. SKIN FOLD THICKNESS
3. WEIST HIP RATIO
4. OTHERS

14.  Skin Fold Thickness-:It is a rapid and "non-invasive”
method for assessing body fat. Several varieties of
callipers (e.g., Harpenden skin callipers)
- The measurement may be taken at all the four sites -
mid-triceps, biceps, sub scapular and suprailiac
regions.
- The sum of the measurements should be less than 40
mm in boys and 50 mm in girls
 Waist-Hip Ratio-: There is an increased risk of
metabolic complications for men with a waist
circumference > 102 cm, and women with a waist
circumference > 88 cm
- Over the past 10 years or so, it has become accepted
that a high WHR (> 1.0 in men and > 0.85 in women)
indicates abdominal fat accumulation.

15. RISK OF HEALTH PROBLEMS WITH OBESITY

16. HAZARDS OF OBESITY
 Increased Morbidity
 Increased Mortality

17. PREVENTION AND CONTROL
 Dietary Changes
 Increased Physical Activity
 Others-:
- Surgical treatment gastric bypass,
gastroplasty, jaw wiring
-Health education has an important role to play
in teaching how to reduce overweight and prevent
obesity.