Obesity PDF

Obesity Sara Hennawi, MD Lecturer of pediatrics Definition Obesity refers to an excess of body fat; in clinical practice, this is estimated by the relationship between height and weight, taking into account age and sex How to measure fat percent 1- Skinfold Testing 2- How to assess ❖ Growth cha...

Obesity Sara Hennawi, MD Lecturer of pediatrics Definition Obesity refers to an excess of body fat; in clinical practice, this is estimated by the relationship between height and weight, taking into account age and sex How to measure fat percent 1- Skinfold Testing 2- How to assess ❖ Growth charts (provided by CDC or WHO) are used for assessment - For children less than 2 years of age: weight percentiles and weight for length charts are used. - For children and adolescents ages 2–20: Body mass index (BMI) percentile is used. - For children and adolescents ages 2–20 with BMIs greater than the 95th percentile: Use percent of the95th percentile Categories of weight status Underweight: less than 5th percentile Healthy weight: 5–84th percentile Overweight: 85–94th percentile Class 1 obesity: 95th percentile to 119% of the 95th percentile Class 2 obesity: 120–139% of the 95th percentile or a BMI greater than 35 kg/m2 and less than 39 kg/m2 Class 3 obesity: greater than 140% of the 95th percentile or BMI greater than 40kg/m2 BMI vs. age is shown for children ages 2–20 years Pathophysiology of obesity: 1- Environmental factors Food supplies and Increasing sedentary consumption Decreasing time spent activities High-calorie in physical activities Television watching Palatable food Use of electronic devices Served in large portions Positive energy balance and weight gain 2- Genetic factors - The heritability of BMI is estimated between 40% and 70% on the basis of twin, family, and adoption studies. - Single-gene mutation (monogenic) obesity is rare. Most of the single-gene mutations identified are connected to the leptin-melanocortin pathway and may be present in as many as 6% of individuals with severe, childhood-onset obesity. Leptin- melanocortin pathway Pathogenesis of complications Adipocytes synthesize adipokines (cell-signaling proteins) and hormones, the secretion rates and effects of which are influenced by the distribution and amount of adipose tissue present. Excessive secretion of proinflammatory adipokines by adipocytes and macrophages within adipose tissue leads to a low-grade systemic inflammatory state in persons with obesity. Elevated levels of free fatty acids, inflammatory cytokines, and lipid intermediates in nonadipose tissues contribute to impaired insulin signaling and the insulin-resistant state that is present in many patients who are overweight or obese Etiological Classification Primary obesity (Also called exogenous obesity or simple obesity): Due to increased/ unhealthful nutritional intake and decreased physical activity Increased or consistent linear growth Precocious puberty can occur  Secondary obesity 1- Endocrinopathies : Hypothalamic/pituitary dysfunction (with growth hormone deficiency) Hypercortisolism (cushinoid features, consider a dexamethasone suppression test or 24-h urinary free cortisol) Hypothyroidism (check thyroid-stimulating hormone (TSH), free thyroxine (T4) test) Pseudohypoparathyroidism Neonatal hyperinsulinemia 2- Genetic syndromes (eg. Down syndrome, Beckwith-wiedemann syndrome) Accompanied by other behavior, functional, or anatomic abnormalities, such as hyperphagia, cognitive delay, dysmorphic features, and organ-specific disorders. Should be suspected in children with obesity and developmental delay. History may include food-seeking behavior such as searching for or stealing food, waking at night to eat, and eating food left behind by others. 3- Monogenic obesity Affects a minority of children with obesity Alteration in single gene leads to early-onset severe obesity Most common is MC4R (melanocortin 4 receptor) variant; other forms include leptin deficiency, leptin receptor variants, and POMC (pro-opiomelanocortin) mutation May be associated with malformation syndromes such as Prader-Willi or Bardet-Biedl syndrome 4- Medications Antipsychotic drugs Glucocorticoids Clinical picture of childhood obesity 1- Height and weight Calculate BMI from weight and height and plot on appropriate growth chart (BMI = weight in kilograms/(height in meters)²) Compare weight gain with height gain: Height and height velocity are usually normal or increased in exogenous obesity while short stature and decreased height velocity suggest possible endocrine cause Waist circumference at level of iliac crest Central obesity more commonly seen in Cushing syndrome 2- Vital signs eg. bradycardia in hypothroidism 3- Skin findings Striae caused by rapid weight gain Violaceous striae may be sign of Cushing syndrome Acanthosis nigricans and skin tags may indicate insulin resistance Severe acne and hirsutism in pubertal girls suggest polycystic ovary disease 4- Signs associated with syndromic obesity include the following: Neurodevelopmental delay Dysmorphic facial features Polydactyly Short stature Hypotonia Individuals with Bardet-Biedl syndrome with some features highlighted. a-d) faces of affected individuals; e) hands showing brachydactyly; f) dental crowding; g) high-arched palate; h) eye exam image showing deterioration of the retina 5- Signs associated with underlying causes or complications of obesity: Abnormal gait; hip, knee, or foot tenderness; or limited range of motion in hip Hepatomegaly or right upper quadrant tenderness Goiter Premature appearance of secondary sexual characteristics in females Pseudogynecomastia (adipose tissue mimicking breast development) Complications and associated comorbidities Diagnostic work up 1- Fasting blood glucose or a hemoglobin A1c (HbA1c) test will determine whether glycemic dysregulation is present. 2- Fasting lipid profile or a non-fasting lipid profile, if fasting is not feasible, can assess dyslipidemia. 3- Liver function tests, specifically alanine aminotransferase (ALT) and aspartate aminotransferase (AST), can screen for non-alcoholic fatty liver disease. 4- 25-hydroxy (25 OH) vitamin D test as many children are at risk for vitamin D deficiency. 5- Blood pressure is checked if the child is older than three years of age. 6- Other studies are indicated based on history: Sleep study for any history of snoring, daytime sleepiness, disrupted sleep cycle or even hyperactivity may be indicated. Liver imaging can be done if the liver function tests (ALT and AST) are high. Uric acid can be obtained in those children with diabetes or prediabetes. Uric acid can be elevated with high intake of high fructose corn syrup and even table sugar. Management of obesity Aims for: Weight loss or weight maintenance during linear growth Prevention of obesity-related complications Referral to specialist is recommended if: Refer to an endocrinologist if a hormonal cause of obesity is suspected or if diabetes is diagnosed Refer to an appropriate specialist based on complications and suspected causes (eg, orthopedic surgeon, geneticist, psychologist) Refer to a multidisciplinary obesity clinic if obesity is severe and does not improve after initial treatment stages Treatment 1- Intensive health behavior and lifestyle treatment is the cornerstone of management for obesity in children ○ Encourage exclusive breastfeeding from birth to age 6 months ○ Between 12 and 24 months, there is no evidence to recommend reduced-fat cow's milk ○ Limit consumption of sugar-sweetened beverages ○ Encourage intake of fruits and vegetables ○ Limit screen time and avoid use of screen devices during mealtimes ○ Encourage eating breakfast daily ○ Limit dining out, especially fast-food restaurants ○ Encourage family meals ○ Adjust portion sizes appropriately for age; allow child to self-regulate intake ○ Encourage diet rich in calcium and high in fiber ○ Promote moderate to vigorous exercise for at least 60 minutes daily ○ Ensure adequate sleep duration Pharmacologic therapy is appropriate for adolescents and can also be offered to children aged 8 to 11 years Orlistat ○ Approved for weight loss in people aged 12 years or older ○ Reversible pancreatic and gastric lipase inhibitor that limits absorption of dietary fat ○ Gastrointestinal adverse effects may limit use ○ Orlistat decreases the absorption of some fat-soluble vitamins (A, D, E, K) and β-carotene. To ensure adequate nutrition, patients should take a daily multivitamin supplement that contains these fat-soluble vitamins.  Phentermine-topiramate Approved for treatment of obesity in people aged 12 years or older Phentermine Approved for short-term use (a few weeks) for weight loss in people aged 17 years or older Sympathomimetic; results in appetite suppression  Glucagonlike peptide 1 receptor agonists (semaglutide and liraglutide) Both approved for weight loss in people aged 12 years or older and are also treatments for type 2 Administered by subcutaneous injection  Other agents with potential weight loss benefits Metformin is a first line treatment of glycemic control in adolescents with type 2 diabetes Lisdexamfetamine is a stimulant medication similar to phentermine approved for children aged 6 years or older with attention-deficit/hyperactivity disorder and indication for treatment of binge-eating disorder in patients aged 18 years or older; has been used off-label for children with obesity 3- Bariatric surgery can be considered for patients with severe obesity (ie, class 2 or greater obesity; BMI of 35 kg/m² or higher, or 120% of the 95th percentile for age and sex, whichever is lower) Sleeve gastrectomy (more than 70%) is the most commonly performed procedure, followed by Roux-en-Y gastric bypass (more than 25%); adjustable gastric banding is rarely performed