Obesity

Introduction

Overweight and obesity increase the risk for several diseases such as hypertension, ischaemic heart disease, and diabetes mellitus.
Obesity results from an imbalance between energy intake and energy expenditure.
However, more recent researches, have
suggested that genetics, physiological and behavioural factors also play significant roles in the aetiology of obesity.
Management of weight disorders is a two
step process: assessment and management.

Clinical Features

The main symptom of obesity is a complaint of being too fat by the patient or concerned relatives.

Measurements for evaluation

  • Body mass index (BMI) is a surrogate measure for global adiposity for ease of clinical use.
  • Waist circumference: is a surrogate marker for truncal obesity.

BMI is calculated as follows:
BMI = weight in kg divided by height in m, expressed as kg/m²

  • Underweight: <18.5 kg/m²
  • Normal weight: 18.5-24.9 kg/m²
  • Overweight: 25-29.9 kg/m²
  • Obesity (Class1): 30-34.9kg/m²
  • Obesity (Class 2):35-39.9 kg/m²
  • Morbid obesity (Class 3): > 40 kg/m²
  • Super morbid obesity: > 50 kg/m²

Truncal obesity: waist circumference and/or waist/hip ratio (WHR).
Upper limits: 102 cm and 88 cm in men and women respectively.

Investigations

Non-specific assessment:, fasting blood
glucose, oral glucose tolerance test, serum lipid profile. Assessment of other
complications as indicated.
Specific assessment should be directed
towards identifying underlying specific
causes when suspected.
These include conditions such as

  • Endocrinopathies (hypothyroidism, Cushing’s syndrome, male hypogonadism, Insulinoma CNS disease that affects hypothalamic function, PCOS), genetic syndromes associated with obesity, mental disorders like bulimia nervosa and binge eating disorder, medications such as steroids, atypical antipsychotics

Pathological consequences of obesity

Gastrointestinal

  • Gallstones
  • pancreatitis,
  • abdominal hernia,
  • Non Alcoholic Fatty Liver Disease,
  • GERD

Endocrinology/ Metabolic:

  • Metabolic syndrome
  • insulin resistance
  • impaired glucose tolerance,
  • type 2 DM,
  • ovarian syndrome
  • dyslipidaemia
  • polycystic

Cardiovascular:

Respiratory:

  • Abnormal pulmonary function,
  • obstructive sleep apnea
  • Obesity hypoventilation syndrome

Musculoskeletal:

  • Osteoarthritis
  • gout,
  • low back pain

Gynaecologic:

  • Menstrual irregularities,
  • infertility

Genitourinary:

  • Urinary stress incontinence

Ophthalmologic

  • Cataracts

Neurogenic

  • Idiopathic intracranial hypertension

Cancers:

  • Oesophagus
  • colon
  • gall
    bladder
  • cervix
  • breast
  • uterus
  • kidney
  • prostate

Postoperative events:

  • Atelectasis
  • pneumonia,
  • DVT,
  • pulmonary embolism

Treatment objectives

  • Conventional approach is to reduce energy intake and increase physical activity.
  • Initial goal of therapy should be to reduce body weight by 10% from the individual baseline weight over a period of six months.
  • This can be achieved through the following:
    • Lifestyle modification (diet therapy and physical activity)
    • Behavioural and psychological interventions
    • Pharmacological intervention
    • Bariatric surgery

Lifestyle modifications:

  • Low caloric diets (with reduction of both carbohydrate and fats components) are to ensure deficit of 500 to 1000k calories per day
    from the individual daily nutritional intake to ensure weight loss of 0.5 to 1kg per week.

Physical activity:

  • Moderate levels of exercise (brisk walking, swimming, cycling) for 30 to 45minutes, five days per week is encouraged. Other forms of exercise must be based on physician prescription.

Behavioural and psychological interventions:

  • Behavioural therapy should be aimed at motivating patients in adopting and practising all recommended treatment strategies of obesity management.

Pharmacological intervention:

  • When lifestyle modification and behavioural therapy has failed
  • Useful and approved drugs include orlistat,
  • Bariatric surgery:
  • BMI >35 kg/m2 with co-morbidities or BMI 24 kg/m2 following failure of lifestyle and pharmacologic therapy.