The rapid rise in the prevalence of childhood overweight and obesity is occurring in both industrialized
and developing countries all over the world. Pediatricians and other pediatric health care
providers will play an increasingly important role in the early identification and prevention of
childhood obesity and its associated comorbid conditions [1,2]. Because obesity is usually established
at a young age, the pediatric primary care office is critical to national efforts to reverse the
pediatric obesity epidemic [3]. According to the 1999–2000 National Health and Nutrition Examination
Survey, the prevalence of childhood obesity (at or above the 95th percentile for body mass
index [BMI] on standard reference growth charts) in the United States has grown to 15.3% of 6 to
11 year olds and 15.5% of 12 to 19 year olds [2,4]. Obesity prevalence has been found to be even
higher among minority and economically disadvantaged populations [2,4,5].
CAUSES/RISK FACTORS
Lower levels of daily physical activity by children in the United States have lead to a greater number
of health problems in children than in previous generations. Sedentary lifestyles increase the risk
of childhood medical conditions such as obesity, hypertension, hyperinsulinemia, hypercholesterolemia,
and dyslipidemia [2,6]. Studies show that parent inactivity strongly predicts child inactivity
[7,8]. A recent study examined the self-reported physical activity and dietary intake patterns of
parents and changes in weight status over 2 years in offspring [9]. Girls of parents with high dietary
intake and low physical activity (obesogenic) had significantly greater increases in weight status.
Thus, in addition to family history of obesity, the environment of the home may equally contribute
to the risk for developing obesity in childhood. However, there are also strong arguments for the
effect of the genetic profile and the early nutritional environment on the risk for developing obesity
during childhood [10–15]. Jackson and colleagues provide a strong argument for nutrition-induced
changes in the hypothalamic–pituitary–adrenal axis in the mother and the fetus [10]. It is suggested
that the local availability of nutrients during pregnancy, especially in relation to protein intake, may
negatively affect future metabolic health. Adjustments may occur to protect brain tissue preferentially
over visceral and somatic growth, resulting in an altered metabolic profile [10]. Thus, nutrition
during pregnancy may have strong implications for future obesity and related chronic disease.
Infancy is also considered a critical period for obesity development. A high protein intake at
the age of 2 years was shown to promote increased fatness at 8 years of age, suggesting that a
high-protein diet early in life could promote an increased risk of obesity later in childhood, but
findings in this area are limited and have not been consistent [16]. Moreover, research generally
supports that children who were breastfed have a lower risk of obesity than those who were formulafed
[17–20]. In addition, those infants who breastfed for longer durations showed an even lower
risk of childhood obesity [21]. Differences in feeding between breastfed and formula fed infants
may also have a critical influence on infant weight gain. Therefore, low birth weight and breastfeeding
history should be considered factors in obesity development in young children (Table 7.1).
In addition, children with such risk factors may be predisposed genetically and behaviorally to the
early manifestation of subtle, nonsymptomatic metabolic abnormalities that lead to childhood
obesity and related chronic disease [22–28]. Therefore, strategies that positively alter the nutrition
and physical activity behaviors and environment of the family may reduce the risk of obesity in
young children, especially in those with one or more risk factors. A recent publication of the
American Academy of Pediatrics offers pediatric obesity prevention guidelines for medical professionals,
which include increased monitoring of at-risk children and parent education [2].
Pediatric health care providers should recognize that environmental factors may greatly affect
physical activity patterns. Unsafe neighborhoods and lack of adult supervision after school may
increase time spent in sedentary behavior such as watching television and playing DVDs or video
or computer games [29].
COMORBIDITIES
Pediatric obesity is associated with many significant health problems and is strongly linked to increased
risks for adult obesity, related comorbid diseases, and shortened life expectancy [2,6]. Growing
numbers of obese children exhibit early signs of diseases that were once found only in adult populations
including type 2 diabetes mellitus, high blood pressure, and abnormal lipid profiles [3]. Obese
children are at an increased risk for diseases that can affect the cardiovascular, pulmonary, endocrine,
and gastrointestinal systems, as well as orthopedic conditions and psychological health problems
[2,6]. Comorbidities affecting the cardiovascular system include hypercholesterolemia, hypertension,
and dyslipidemia [2,6a,30]. Endocrine system comorbidities include hyperinsulinemia, insulin
resistance, impaired glucose tolerance, type 2 diabetes mellitus, and menstrual irregularity [2].
Common pulmonary and gastrointestinal comorbidities include sleep apnea, asthma, obesity hypoventilation
syndrome, and nonalcoholic steatohepatitis [2,29]. Common orthopedic comorbidities
include slipped capital femoral epiphysis, Blount disease (tibia varia), and genu varum. Mental
health problems may include depression and low self-esteem [2,6,29].
TREATMENT APPROACHES
Several weight loss approaches can be considered when choosing a treatment plan for an overweight
or obese patient. Because obesity is a multifactorial disease, treatment of the disease is approached
from many angles including diet modification, increased physical activity, psychological intervention,
pharmacotherapy, and surgery. Reduction of energy intake is a mainstay of treatment, but the ideal
approach will vary with the skills and motivation of the family, the severity of the overweight
status, and the age of the child. Caution should be used in prescribing “diets” for children, except
under well-supervised conditions because of the risks associated with overly restrictive access to
food. This has been associated (in young children) with decreased ability to self-regulate energy
intake [31,32]. In adolescents, dieting was inversely associated with BMI [33]. Several dietary
approaches can be considered including low fat, low carbohydrate, high protein, and low glycemic
index. The Traffic Light Diet (see Appendix A3.3B), which applies principles of foods with high
versus low caloric density, has been shown to be easy for children to understand and successfully
follow [34]. Other popular treatments focus on psychological and family therapy, including behavioral
modification [35]. Behavioral modification has been shown to increase the success of obesity
treatment and includes such elements as goal setting, maintaining a food diary, reducing availability
of high-calorie stimulus foods, positive reinforcement, and parental support [34]. Health providers
should seek training in health behavior change techniques, parent limit-setting strategies and
reinforcement skills, and family conflict awareness [36]. Dietary treatment should be accompanied
by efforts to emphasize increased physical activity [34,35]. However, exercise alone is generally
not sufficient to promote significant weight loss without diet modification [34]. Physical activity
provides additional health benefits and is linked to successful maintenance of weight-loss. Reduction
of sedentary activities such as television viewing, video games, and computer time may be especially
effective targets for behavior change [6a,37,38].
Pharmacotherapy is sometimes a useful adjunct to diet, activity, and behavioral change strategies.
Examples specific for obesity treatment include sibutramine and orlistat, but each has significant
potential side effects, and efficacy data are limited. Bariatric surgery has been successfully
performed on severely obese adolescents. Guidelines for patient and site selection have been
published [39]. Criteria include a BMI of at least 40, accompanied by significant comorbidities
such as obstructive sleep apnea, type 2 diabetes mellitus, and pseudotumor cerebri. This treatment
is best undertaken in a center that has surgeons with experience with the procedure in adolescents,
and at which a multidisciplinary team is available. The procedure appears to be safe in the short
term, and weight loss is typically substantial, with improvement in comorbidities. There are
currently few data on long-term outcomes and complications [34,35,40].
DIAGNOSIS
Early diagnosis and treatment of obesity in children is crucial for the successful management of
pediatric health [2,41,42]. Unfortunately, although childhood obesity has now reached epidemic
levels, this disease is still under-recognized by the health care community [43]. In addition,
underdiagnosis is generally more prevalent than misclassification of obesity [44]. Recently, O’Brien
et al. [43] reported that pediatric health care providers diagnosed overweight in only one-half (53%)
of overweight children examined for health supervision. Moreover, in children diagnosed as overweight
by their physicians, comprehensive treatment programs were not generally prescribed [43].
One study has shown that although plotting BMI enhanced physician recognition of overweight
when compared with plotting height and weight for age, survey data in the same report indicatedthat
only a minority of pediatricians routinely use BMI [45]. In Chapter 4 of this volume, Gordon
provides similar disappointing rates of diagnosis and referral in overweight children in primary
care settings [46]. Kiess and colleagues provide a diagnostic algorithm for childhood obesity that
primary care providers can use to determine the most appropriate management plan (Figure 7.1) [35].
MEDICAL HISTORY
Pediatric obesity is a complex condition that is associated, as noted above, with a plethora of
medical complications, syndromes, and disorders. An expert panel report [47] suggests that the
initial diagnosis should begin with a thorough screening of the patient’s medical history. Conditions
of primary concern are hypertension, endocrine disorders, orthopedic problems, type 2 diabetes
mellitus (or insulin resistance), genetic syndromes, sleep disorders, pseudotumor cerebri, and
gastrointestinal disorders.
As part of this medical history, information on the child’s current eating and physical activity
patterns should be obtained, with a particular focus on behaviors that can be targeted for change.
An expert committee has [29] emphasized that both food type and patterns of eating should be
assessed to discern origins of excess caloric intake. Likewise, the assessment of physical activity
patterns and extent of sedentary behaviors provides information important to increasing energy
expenditure [29]. A comprehensive medical history and physical examination form may be found
in Appendix A1.6.
FAMILY HISTORY
Critical to assessment of a child’s risk from overweight is the documentation of the family history
of disease. The recommended conditions to evaluate when obtaining family history from the patient
include overweight, dyslipidemia, hypertension, cardiovascular disease, gallbladder disease, eating
disorders in parents, type 2 diabetes mellitus, and other endocrine abnormalities [47]. Emerging
research indicates that the health status of the mother immediately before pregnancy, during
pregnancy, and during breastfeeding may also be important [48]. Whitaker tracked the weight status
of preschool children whose mothers were obese during pregnancy. These youth were twice as
likely to be overweight as children whose mothers maintained a healthy weight during pregnancy
(Figure 7.2) [49].
SOCIAL HISTORY
The structure of the family, school and child care arrangements, living situation, parental employment,
and history of abuse are examples of information to be obtained in the social history, which
will inform the negotiations for health behavior changes.
REVIEW OF SYSTEMS
The review of systems should address symptoms of potential comorbidities of overweight. Examples
include asking about the presence of headaches; visual changes; sleep problems such as snoring,
restless sleep, inability to lie supine, and daytime somnolence; shortness of breath or wheezing;
chest pain; abdominal pain; and joint and skeletal muscle complaints. A brief evaluation of the
child’s psychological status is also useful.
PRIMARY RISK FACTORS
The children who are at the highest risk for becoming obese are those who belong to economically
disadvantaged minority populations (Table 7.1). As a result of having a low socioeconomic status,
children may have less access to safe places for physical activity and/or less access to healthful
food choices such as fruits and vegetables. Recent studies show a consistent rise in the prevalence
of obesity among preschool children from low-income families [50]. These children often have
low levels of cognitive stimulation, which is associated with a significant increase in the risk for
early-onset obesity [51]. Other risk factors that have been linked to an increased risk include
unhealthy family and parental dynamics, low or high birth weight, maternal diabetes and obesity,
high prevalence of obesity in other family members, and overcontrolling parental behavior (Table
7.1) [2].
PHYSICAL EXAM
As for all patients, a patient who is found to be overweight should have a physical examination,
in this case with a focus on signs of comorbid conditions that may be present or on any underlying
conditions that may contribute to excessive weight gains, such as hypothyroidism, reactive airways
disease, tonsillar hypertrophy (contributing to airway obstruction), genu varum (flat feet) or other
orthopedic conditions, and genetic or endocrine abnormalities [41]. A patient with insulin resistance
may show signs of acanthosis nigricans (darkening of the skin). Hypothyroidism should be suspected
with excessive weight gain and plateauing of linear growth; exam findings may include skin
and hair changes, enlarged thyroid, and absent deep tendon reflexes. An abdominal exam should
assess liver size and tenderness. Postural and gait abnormalities may indicate the presence of
orthopedic conditions such as genu varum. Tanner stage should be evaluated and assessed in relation
to the child’s age. Rare genetic and endocrine abnormalities may manifest themselves through
dysmorphic features including abnormal genitalia, developmental delay, poor linear growth, hirsuitism,
and striae [41]. Blood pressure measurements should also be obtained using an appropriately sized
blood pressure cuff.
BODY MASS INDEX
Background
The World Health Organization, the Centers for Disease Control and Prevention, and many national
organizations recommend the use of BMI to identify overweight and obesity in youth [2,52,53].
BMI is a convenient measurement for screening for overweight in children. Standard BMI classifications
define a BMI between the 85th and 95th percentiles for age and sex as “at risk for
overweight,” and a BMI greater than the 95th percentile for age as “overweight” (Appendix A1.10).
BMI is an accepted screening tool for use by pediatric health care providers as a result of its use
of easily accessible data (weight and height) and moderately strong correlation with laboratory
measurements of body fatness [2,3,54].
Calculating Obesity Risk and Status with BMI Percentiles
Pediatric growth charts for the U.S. population now include BMI percentile grids for age and gender
and can be used for longitudinal tracking of a patient’s BMI from ages 2 through 20 years, and to
identify overweight (see Appendix A1.10) [29,53]. BMI is calculated by applying one of the
following formulas:
weight (kilograms)/height (meters)2
or
[weight (pounds)/height (inches)2] × 703.
Diagnosis
Once BMI is calculated, the physician or health care provider can determine risk and status by
plotting on Centers for Disease Control and Prevention growth charts (see Appendix A1.10). This
should be done at least annually to facilitate the early recognition of overweight and to monitor
weight increases relative to linear growth [2]. If a trend for excessive weight gain is established
(e.g., crossing BMI percentile channels or an increase of three to four BMI units in 1 year),
contributing factors should be explored and discussed with parents to prevent further progression
of excessive weight gain or overweight status. Research, although limited, indicates that early
treatment is associated with improved long-term success [29].
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