BMI (body mass index; BMI = wt (kg) ÷ Ht2 (m)) is a convenient screening tool that correlates fairly strongly with body fatness in children and adults. BMI age-specific and gender-specific percentile curves (for 2to 20-year-olds) allow an assessment of BMI percentile (available online at http://www.cdc.gov/growthcharts ). Table 29-3 provides BMI interpretation guidelines. For children younger than 2 years of age, weight-for-length measurements greater than 95th percentile may indicate overweight and warrant further assessment. A BMI for age and gender above the 95th percentile is strongly associated with excessive body fat and is associated with multiple cardiovascular disease risk factors.
Early recognition of excessive rates of weight gain, overweight, or obesity in children is essential because the earlier the interventions, the more likely they are to be successful.
Alström syndrome Hypogonadism, retinal degeneration, deafness, diabetes mellitus
Carpenter syndrome Polydactyly, syndactyly, cranial synostosis, mental retardation
Hyperinsulinism Nesidioblastosis, pancreatic adenoma, hypoglycemia, Mauriac syndrome
Laurence-Moon-Bardet-Retinal degeneration, syndactyly, Biedl hypogonadism, mental retardation, autosomal recessive syndrome
Muscular dystrophy Late onset of obesity
Prader-Willi syndrome Neonatal hypotonia, normal growth immediately after birth, small hands and feet, mental retardation, hypogonadism; some have partial deletion of chromosome 15
Pseudohypoparathyroidism Variable hypocalcemia, cutaneous calcifications
Turner syndrome Ovarian dysgenesis, lymphedema, web neck; XO chromosome *These diseases represent <5% of cases of childhood obesity.
www.cdc.gov/healthyweight
Routine evaluation at well-child visits should include the following: 1.
Anthropometric data, including weight, height, and calculation of BMI. Data should be plotted on age-appropriate and gender-appropriate growth charts and assessed for BMI trends (see Table 29-3).
2.
Dietary and physical activity history (Table 29-4). Assess patterns and potential targets for behavioral change.
3.
Physical examination. Assess blood pressure, adiposity distribution (central versus generalized), markers of comorbidities (acanthosis nigricans, hirsutism, hepatomegaly, orthopedic abnormalities), and physical stigmata of a genetic syndrome (explains fewer than 5% of cases).
4.
Laboratory studies. These are generally reservedfor children who are obese (BMI > 95th percentile),who have evidence of comorbidities, or both. Other studies should be guided by findings in the historyand physical examination. The American Academy ofPediatrics endorses the government guidelines from2011, which recommend that all 9to 11-year-olds bescreened for cholesterol. Other useful laboratory testsmay include hemoglobin A1c, fasting lipid profile,fasting glucose levels, liver function tests, and thyroidfunction tests (if there is a faster increase in weightthan height).
The approach to therapy and aggressiveness of treatmentshould be based on risk factors, including age, severity ofoverweight and obesity, and comorbidities, as well as familyhistory and support. The primary goal for all children withuncomplicated obesity and fast-rising weight-for-height isto achieve healthy eating and activity patterns. For children with a secondary complication, specific treatment of thecomplication is an important goal. Childhood and adolescentobesity treatment programs can lead to sustained weight lossand decreases in BMI when treatment focuses on behavioral changes and is family centered. Concurrent changes in dietaryand physical activity patterns are most likely to provide success (Table 29-5).