Obesity in Paediatrics
1. Definition
Paediatric obesity is an abnormal or excessive accumulation of body fat that presents a risk to health in children and adolescents.
Diagnosis is based on Body Mass Index (BMI) for age percentiles rather than absolute BMI.
BMI = Weight (kg) / Height (m²)
Classification using WHO or CDC growth charts:
| Category | BMI Percentile |
| -------------- | ------------------------ |
| Underweight | <5th percentile |
| Normal weight | 5th–84th percentile |
| Overweight | 85th–94th percentile |
| Obesity | ≥95th percentile |
| Severe obesity | ≥120% of 95th percentile |
2. Pathophysiology
Paediatric obesity results from chronic positive energy balance where energy intake exceeds energy expenditure.
Mechanisms
- Adipocyte hypertrophy and hyperplasia
* Increased fat cell size and number
- Hormonal dysregulation
* Increased insulin
* Leptin resistance
* Altered ghrelin levels
- Inflammation
* Adipose tissue releases cytokines
* TNF-α
* IL-6
* CRP
- Insulin resistance
* Leads to hyperinsulinemia
* Increased fat storage
- Genetic susceptibility
* Appetite regulation disorders
3. Causes / Risk Factors
A. Lifestyle Factors
- High calorie diet
- Fast food consumption
- Sugary beverages
- Sedentary lifestyle
- Excess screen time
- Lack of physical activity
B. Genetic Factors
- Family history of obesity
- Monogenic obesity disorders
Examples
- Prader–Willi syndrome
- Bardet–Biedl syndrome
C. Endocrine Causes
Rare but important:
- Hypothyroidism
- Cushing syndrome
- Growth hormone deficiency
D. Perinatal Factors
- Maternal diabetes
- High birth weight
- Rapid infant weight gain
- Lack of breastfeeding
E. Psychological Factors
- Emotional eating
- Stress
- Depression
4. Clinical Features
Anthropometric Features
- BMI ≥95th percentile
- Increased waist circumference
- Central obesity
Physical Signs
- Acanthosis nigricans (insulin resistance)
- Striae
- Gynecomastia (boys)
- Early puberty
Symptoms
- Fatigue
- Shortness of breath
- Exercise intolerance
- Joint pain
5. Complications
Metabolic Complications
- Type 2 diabetes
- Dyslipidemia
- Metabolic syndrome
- Hypertension
Cardiovascular
- Early atherosclerosis
- Left ventricular hypertrophy
Respiratory
- Obstructive sleep apnea
- Hypoventilation syndrome
Gastrointestinal
- Non-alcoholic fatty liver disease (NAFLD)
- Gallstones
Orthopedic
- Slipped capital femoral epiphysis
- Blount disease
Psychological
- Low self-esteem
- Depression
- Social isolation
6. Investigations
Anthropometric Assessment
- BMI percentile
- Waist circumference
- Growth chart plotting
Laboratory Tests
| Test | Purpose |
| ---------------------- | ------------------ |
| Fasting blood glucose | Diabetes screening |
| HbA1c | Glycemic control |
| Lipid profile | Dyslipidemia |
| Liver function tests | NAFLD |
| Thyroid function tests | Hypothyroidism |
| Fasting insulin | Insulin resistance |
Additional Tests (if indicated)
- Sleep study for OSA
- Ultrasound abdomen for fatty liver
7. Differential Diagnosis
Conditions causing secondary obesity:
- Hypothyroidism
- Cushing syndrome
- Growth hormone deficiency
- Genetic syndromes
- Hypothalamic disorders
8. Management
Management is multidisciplinary involving diet, exercise, behavioral therapy, and sometimes medications.
Stepwise Treatment Approach
Step 1: Lifestyle Modification (First-line)
Dietary Therapy
Goals:
- Reduce calorie intake
- Improve nutrition quality
Recommendations:
- Balanced diet
- Increase fruits and vegetables
- Reduce sugar intake
- Avoid sugary drinks
- Reduce fast foods
- Portion control
Physical Activity
Children should perform:
≥60 minutes moderate to vigorous physical activity daily
Examples:
- Running
- Cycling
- Swimming
- Outdoor games
Limit screen time to <2 hours/day
Behavioral Therapy
- Family-based lifestyle modification
- Goal setting
- Self-monitoring
- Positive reinforcement
Parents play a crucial role.
9. Pharmacological Treatment
Used only when BMI ≥95th percentile with complications or severe obesity.
Orlistat
Indication
Obesity in adolescents ≥12 years when lifestyle therapy fails.
Mechanism of Action
- Pancreatic lipase inhibitor
- Reduces fat absorption by about 30%
Usual Dose
- 120 mg orally three times daily with meals containing fat
Pharmacokinetics
- Minimal systemic absorption
- Acts locally in gastrointestinal tract
Adverse Effects
Common
- Oily stools
- Flatulence
- Fecal urgency
- Steatorrhea
Serious
- Fat-soluble vitamin deficiency
Contraindications
- Chronic malabsorption syndrome
- Cholestasis
Drug Interactions
- Warfarin
- Cyclosporine
- Fat-soluble vitamins
Monitoring
- Weight and BMI
- Fat-soluble vitamins (A, D, E, K)
Patient Counselling
- Maintain low-fat diet
- Take multivitamins at bedtime
- Expect gastrointestinal effects
10. Bariatric Surgery
Considered in severe adolescent obesity.
Criteria:
- BMI ≥40
OR
- BMI ≥35 with serious complications
Types
- Gastric bypass
- Sleeve gastrectomy
Requires specialized centers.
11. Prevention
Early Prevention Strategies
- Exclusive breastfeeding for 6 months
- Healthy complementary feeding
- Encourage active lifestyle
- Reduce junk food
- Family healthy eating habits
- Limit screen exposure
12. Prognosis
Untreated childhood obesity often persists into adulthood.
Consequences:
- Early cardiovascular disease
- Type 2 diabetes
- Reduced life expectancy
Early intervention improves long-term outcomes.
If you want, I can also give:
• 50 MCQs on paediatric obesity (exam oriented)
• OSCE / viva points for paediatrics exams
• Short notes format for medical exams
• Complications table for quick revision
