Obesity

Definition

Obesity is defined as body mass index (BMI) greater than or equal to the 95th percentile for age and sex with/without any complications. [BMI is expressed as body weight in kilograms/square of height in meters (kg/m2)].

Causes of Obesity

Though the list of endogenous obesity is vast, the primary cause of obesity in children is exogenous either due to overeating, inadequate exercise, or an eating disorder.

The endogenous causes of obesity are:

• Genetic disorders: Lawrence Moon Biedl syndrome and Cohen's syndrome. They present with dysmorphic features, developmental delay and sometimes retinal changes and deafness in addition to obesity.

Children with Prader Willi syndrome have growth failure and have almond-shaped eyes. Males have undescended testes.

• Endocrine disorders: Hypothyroidism - Presents with poor linear growth, mental subnormality, bradycardia, and constipation with/without a goiter.

Cushing's syndrome - It also presents with poor linear growth, hirsutism, truncal obesity, and violaceous striae.

The exogenous causes of obesity usually cause the child to be tall, though ultimately the adult height may be less. All the endogenous causes of obesity are associated with delayed bone age. However, exogenous obesity may cause advanced bone age.

How is An Obese Child Managed?

The child is first assessed for the degree of obesity. Although measurement of skinfold thickness may be unreliable, at triceps skinfold thickness higher than the 95th percentile suggests that the child is overweight (triceps skinfold thickness is measured at the midpoint between the acromion and olecranon process on the posterior surface of the right arm, with the arm relaxed and measured with a caliper). Visceral obesity is measured directly by a CT scan or MRI to find out the risk of cardiovascular disease. After calculating the BMI, the child is evaluated for the cause of obesity. Usually, children with endogenous obesity are short and have delayed done age whereas those with exogenous causes are tall and have advanced bone age. It is always imperative to rule out hypothyroidism in every case of obesity and a T3, T4, TSH level may be useful. If Cushing's syndrome is suspected, urine free cortisol or dexamethasone suppression test may be indicated. The genetic disease may require karyotyping including high-resolution banding.

Complications like pseudotumor cerebri, sleep apnea, obesity hypoventilation syndrome and orthopedic problems may require referral to the pediatric obesity treatment centers. Children younger than 2 years of age with severe obesity require evaluation in a pediatric obesity center before treatment is considered.

A lipid profile should be done if there is a family history of myocardial infarction before 50 years of age, hypertension, and dyslipidemias to rule out dyslipidemias.

Once, the child has been evaluated for the cause and complications of obesity, the treatment is initiated. The main criteria of treatment are weight control in all overweight children of 2 years of age. i.e. maintenance of baseline weight. It allows a gradual decrease in BMI as the child grows in height. For children more than 7 years of age, weight maintenance may be continued if there are no secondary complications and BMI is between 85th and 95th percentile. However, if the BMI is above the 95th percentile, or associated with complications, then weight loss is recommended. It is recommended to have a weight loss of 0.5 kg per month. The goal should be to achieve a BMI below the 85th percentile.

To achieve the above goals, intervention should begin early. The most important aspect is that the family should be ready to accept change. The family should be informed about the complications of obesity. The family and all caregivers should participate in the treatment program. The family should be taught to monitor eating and activity in the child. The treatment programs should be directed towards a permanent change. The best way to achieve all this is diet modification and increase the activity level of the child. Instead of calculating the number of calories consumed in a day, reduction or elimination of specific food may reduce the calories without making the patient feel hungry or deprived. The patient can refrain from eating one or two high caloric food such as biscuits, ice-cream, fried foods, etc. Even a 100 kcal deficit per day could lead to a 5 kg loss of weight in a year. Another way to maintain weight is to reduce inactivity. The best way to do that would be to limit television viewing to 1 to 2 hours per day.

The goal of therapy is healthy eating and activity and not the attainment of ideal body weight.

Complications

Obesity can lead to many complications. Also, a history of cardiovascular disease, hypertension or dyslipidemias in first blood relatives increases the risk of complications in the child. The following complications are seen:

• Orthopedic complications:
  *Slipped capital femoral epiphysis. It presents as hip or knee pain and a limited range of movement at the hip joint.

  *Blount's disease (tibia vara) - It presents as bowing of the leg.

• Pseudotumor cerebri: The child may complain of severe headaches. The optic discs on ophthalmoscopy may show blurred margins. The child is at risk of visual defect or vision loss.
• Sleep apnea/Hypoventilation syndrome: The child may suffer from daytime somnolence or breathing difficulty during sleep. They are potentially fatal disorders that require rapid weight loss and may require continuous positive airway pressure until weight loss decreases intra-abdominal pressure, improves chest wall compliance and adequate ventilation is restored.
• Gall bladder disease:- The child may have abnormal pain or tenderness. Ultrasonography is useful to detect the condition. Obesity ComplicationsEndocrine disorders:-
• Polycystic ovary disease: Obese females may present with oligomenorrhoea or amenorrhoea and hirsutism. It is detected by ultrasonography and LH: FSH ratio.
• Non-insulin-dependent diabetes mellitus (NIDDM): The child may have coarse hyperpigmented areas in the neck folds or axilla along with polyuria, polyphagia, and polydipsia, both fasting glucose and fasting insulin levels should be done to rule out insulin resistance.
• Hypertension, dyslipidemias: A lipoprotein test should be done in every child to detect dyslipidemias. LDL level >130 mg% but less than 180 mg% is suggestive of obesity and requires diet and exercise modification. LDL level >180 mg% shall require medical treatment in addition to diet modification. These children are at later risk of early-onset adult coronary heart disease, myocardial infarction, and diabetes.

What are the complications that can occur on these weight-management programs?

If weight loss is very rapid, then there are chances of developing gall bladder disease and malnutrition. Also, linear growth may start slowing. The effect of rapid weight loss (>0.5 kg/month) in children younger than 7 years is unknown.

Emotional problems may arise in the child. He may develop eating disorders and develop low self-esteem.