Clinical Manifestations

In addition to advanced height, growth, and sexual maturation, obesity in childhood and adolescence is associated with a number of other clinical manifestations (Table 5-24). These problems are more common at the upper extremes of obesity, and most are found in a minority of obese children and adolescents. The more common obesity-associated problems (ie, dyslipidemias, hyperinsulinemia), however, are found in more than half of overweight children and adolescents. In addition, the results of several longitudinal studies suggest that overweight children and adolescents may have increased risks of morbidity and mortality in adulthood regardless of their adult weight status. The greatest risks are associated with persistence of obesity into adulthood or adult-onset obesity. Among obese adults, the clinical manifestations become more prevalent and serious. In addition to the problems noted in Table 5-24, obese adults are at increased risk of overall mortality and death from cardiovascular diseases, cancer, diabetes, and digestive diseases. They also are more likely to suffer from osteoarthritis and have complications of pregnancy. Recent studies suggest that the economic costs of obesity in the United States approach $100 billion per year.

Clinical Manifestations

In addition to advanced height, growth, and sexual maturation, obesity in childhood and adolescence is associated with a number of other clinical manifestations (Table 5-24). These problems are more common at the upper extremes of obesity, and most are found in a minority of obese children and adolescents. The more common obesity-associated problems (ie, dyslipidemias, hyperinsulinemia), however, are found in more than half of overweight children and adolescents. In addition, the results of several longitudinal studies suggest that overweight children and adolescents may have increased risks of morbidity and mortality in adulthood regardless of their adult weight status. The greatest risks are associated with persistence of obesity into adulthood or adult-onset obesity. Among obese adults, the clinical manifestations become more prevalent and serious. In addition to the problems noted in Table 5-24, obese adults are at increased risk of overall mortality and death from cardiovascular diseases, cancer, diabetes, and digestive diseases. They also are more likely to suffer from osteoarthritis and have complications of pregnancy. Recent studies suggest that the economic costs of obesity in the United States approach $100 billion per year.

While the physical complications of obesity pose significant problems to a minority of overweight children and adolescents, the psychological and social consequences may be much more common. In several studies during the 1960s, diverse samples of children and adults associated negative stereotypes with representations of obese children and ranked them as less likable than representations of children with physical disabilities. Obesity has been associated with lower college acceptance rates, lower desirability to employers, prospective attainment of lower social class, and increased risk for body dissatisfaction and binge eating and purging behaviors among adolescent girls. However, some studies have shown that children’s actual rating of liking and disliking are unrelated to the weight status of their peers, and obese children do not score consistently lower than normal-weight peers on formal assessments of social and emotional functioning. Similarly, although low self-esteem and more depressive symptoms have been documented in some clinical samples of obese children, this has not been the case in population-based, nonclinical samples.

Assessment and diagnosis

The goal of the initial clinical evaluation should be:

• To assess the extent of overweightness;
• To identify existing associated morbidity;
• To assess the level of associated risk;
• To identify important family or environmental factors;
• To rule out the rare endocrinologic and genetic disorders that an associated with obesity; and
• To design a treatment plan.

Rare congenital and endocrinologic disorders that may be associated with obesity include Alstrom syndrome; Carpenter syndrome; Cohen syndrome; Cushing syndrome; growth hormone deficiency; hyperinsulinemia (eg, pancreatic tumor, pancreatic beta-cell hypersecretion, hypothalamic lesion); hypothyroidism; Laurence-Moon (Bardet-Biedl) syndrome; polycystic ovary (Stein-Leventhal) syndrome; Prader-Willi syndrome; pseudohypoparathyroidism; and Turner syndrome. With the exception of hyperinsulinemia, all of these disorders generally are associated with short stature; delayed growth and sexual maturation; developmental delay or mental retardation; and other distinct functional, morphologic, or physiological abnormalities. In contrast, “primary” obesity generally is associated with advanced height, growth, and sexual maturation. Thus, genetic and endocrinologic disorders with associated obesity, which account for less than 1% of obesity among children and adolescents, usually can be ruled out based on a careful history and physical examination.

Initial assessment of an overweight child should include a history of linear growth as well as weight, age at onset of obesity, pubertal history (if applicable), and detailed diet and physical activity histories. An informal diet and activity history, reviewing the intake of total and saturated fat and calorically dense foods on a typical day, also may be sufficient. A careful review should seek symptoms associated with the congenital and endocrinologic “causes” and complications listed in Table 5-24 such as headaches; visual changes; menstrual history (if applicable); polydypsia; polyuria; nocturia; lower extremity pain; daytime somnolence; snoring; or abdominal discomfort, as well as an assessment of depressive symptoms and disordered eating attitudes and behaviors. A family history should include questions about obesity, diabetes, hypertension, hyperlipidemias, cerebrovascular disease, coronary heart disease, and gallbladder disease. The parents’ and child’s opinions regarding the cause, as well as impact of the problem, should be explored in detail, with particular attention paid to lack of consensus among parents and children, impact on other family members, assignments of blame, denial, and expectations for weight loss.

A full physical examination is indicated, with emphasis on findings associated with obesity and symptoms identified by the history (eg, if headaches are present, a funduscopic and neurologic exam should be performed), as well as dysmorphic features; acanthosis nigricans; hirsutism; violaceous striae; abdominal tenderness; undescended testes; limited hip range of motion; and lower leg bowing. If height is greater than or equal to the 50th percentile for age and the history and physical examination are not suggestive, endocrinologic and congenital causes can essentially be ruled out. Every patient should have blood pressure measured.

A fasting insulin and lipid profile are recommended to detect the more common obesity-associated morbidities and to monitor during treatment. Otherwise, laboratory assessments are rarely useful unless they are specifically indicated based on findings from the history and/or examination. Thyroid function tests or a bone age may be helpful only to reassure children or parents who are convinced of the “glandular” nature of the obesity, but these are not necessary for a child with normal linear growth. If daytime somnolence or snoring are reported, further workup may include pulmonary function tests, arterial blood gases, sleep study, and otolaryngology evaluation. Complaints of lower extremity pain or bowing should be evaluated with appropriate radiologic studies and an orthopedic evaluation. Right-upper-quadrant abdominal discomfort and/or suggestive findings on physical examination should be followed up with ultrasound evaluation for cholelithiasis.

Body mass index (BMI), which is defined as weight in kilograms divided by the square of the height in meters (kg/m2), is recommended as the primary method for assessing obesity in children and adolescents. Recent national standards by age and sex are now available along with the height and weight growth charts from the National Center for Health Statistics. The 95th percentile has been recommended as the most appropriate cut-off for the clinical definition of obesity. The 95th percentile identifies children who are at a substantial risk for obesity-associated morbidities and likely to become obese adults. Children with a BMI between the 85th and the 95th percentile are defined as overweight, and should also be evaluated thoroughly for obesity-associated complications. In the U.S. population, the 85th and 95th percentiles in children also correspond to adult BMI’s of 25 and 30, respectively, the accepted definitions of adult overweightness and obesity. Clinicians who are practiced at using skinfold calipers may also wish to measure a triceps skinfold thickness. The triceps skinfold thickness and BMI are about equally predictive of associated morbidity. The BMI tracks better into later adolescence and adulthood, however, and is easier and more reliable because it depends only on accurate measures of height and weight. Children and adolescents with increased frame size and well-developed musculature may be overweight for height without being overfat. Skinfolds are most helpful in distinguishing the overfat from the overmuscled child. However, reliable skinfold thickness measurement is difficult and therefore less appropriate for the general clinical setting.

Weight status alone should not be used to diagnose obesity and recommend treatment. The diagnosis of obesity may itself have significant adverse medical, psychological, and social consequences. A medical diagnosis of obesity may induce or further substantiate feelings of inadequacy and guilt, as well as lead to “special treatment” by parents. On the other hand, not all obese children experience adverse psychological or social consequences, and only a minority sustain significant medical complications. Clinical samples tend to differ considerably from nonclinical samples, and there is evidence for ethnic and cultural variations in perceived ideal weight and body shape. In addition, available treatments have been relatively disappointing in achieving long-term weight control, and treatments themselves can result in complications. Consequently, the clinician should judge the appropriateness of diagnosis and treatment on a case-by-case basis, focusing primarily on children and adolescents demonstrating physical (Table 5-24) or psychosocial complications, those at highest risk of developing obesity-related morbidity, and those patients and families who are most highly motivated and most likely to be successful in treatment.