This chapter will address the following American College of Graduate Medical Education competencies: patient care, practice-based learning and improvement, and professionalism.

Patient Care: This chapter will help the pediatric health care provider incorporate evidence-based guidelines for the assessment of obesity into an appropriate and effective treatment plan and set effective lifestyle goals with the patient and family.

Practice-Based Learning and Improvement: Incorporating the “work” of obesity prevention and treatment into practice is new for many health care practitioners. This chapter will help address childhood obesity and obesity-related comorbidities systematically in practice using advances in medical knowledge, epidemiology, and psychosocial and behavioral health to engage in continuous practice-based learning and improvement.

Professionalism: This chapter will review the commitment to ethical principles, sensitivity to diversity and values of respect, compassion and kindness to patients which are particularly important in addressing the sensitive issue of weight and lifestyle behaviors with children and families.

Appropriate assessment is the first step in the treatment of obesity in children and encompasses determining the patient’s body mass index (BMI) classification, considering the differential diagnosis for the etiology of obesity including an evaluation of weight related-behaviors, screening for comorbidities associated with obesity (including risk for developing comorbidities in the future), and exploring readiness to engage in weight management efforts.^{1, 2, 3} A thorough assessment will provide guidance for treatment and may be facilitated by the use of widely available tools^{4, 5, 6} to streamline the process and to help ensure that all necessary components are addressed.

This chapter will describe a detailed approach to assessing obesity in the pediatric primary care setting. BMI should be obtained and monitored annually on all patients and become a vital sign. A thorough medical evaluation should be conducted for all children with obesity, focused on identifying underlying causes of obesity and screening for comorbidities. When children with obesity are short, or 2 standard deviations below the mean,⁷ have learning disabilities or findings suggesting a syndrome, then endocrine and/or genetic causes should be suspected. A thoughtful dietary assessment should be performed that goes beyond the content and quantity of food consumed, but also addresses eating, and food-related behaviors and cultural norms. The assessment of activity should include the duration and intensity of physical activity and the physical activity environment along with the amount of time spent in sedentary (eg, screen time) activities and sleep. Understanding family motivation and readiness to change, perceptions regarding participation in weight management efforts, and specific nutrition and activity-related behaviors are essential prior to beginning efforts to intervene.

While obesity is defined as excess adiposity,⁸ measuring adiposity directly through the gold standard of hydrostatic weighing or through other methods such as taking caliper measurements presents a number of challenges in the primary care setting. Thus, there is consensus that using the proxy of BMI is a good clinical screen for obesity.^{1,9, 10, 11, 12} As a screening tool, it is important to be aware that an elevated BMI may be due to the degree of muscle mass (eg, athletes). However, excess adiposity is a far more likely cause when the BMI is greater than the 95th percentile for age and gender.

Calculating BMI

BMI is calculated using the formula: BMI = weight in kilograms/(height in meters)² or, if using the English system, BMI = (weight in pounds/[height in inches]²) × 703.¹³ Although there are often barriers cited to calculating and plotting the BMI,^14,15 the evidence suggests that relying upon visual inspection is not an effective means to screen for obesity.¹⁶ Therefore, it is recommended that in order to screen for the presence of obesity and to monitor changes in weight status that warrant intervention, a BMI should be calculated at least annually for all children 2 years or older^1,9 and weight for length plotted in children younger than 2 years (using the World Health Organization [WHO] charts; http://www.cdc.gov/growthcharts/).

Classifying weight status

In adults, weight status is determined using the raw BMI (normal weight from 18.5 to < 25, overweight from 25 to < 30, and obesity ≥ 30). However, for children, because of changes associated with development, the appropriate BMI varies with age. Thus, the Centers for Disease Control and Prevention (CDC) growth curves are used to determine BMI percentiles, which are the basis upon which weight status is determined for children older than 2 years.^17,18 The cut points are as follows: children with BMI between the 5th and less than the 85th percentile are classified as being within the healthy range, those with BMI at or above the 85th percentile but less than the 95th percentile are classified as overweight, and those with BMI at or above the 95th percentile are classified as having obesity.¹⁷ For children younger than 2 years, the use of 2006 WHO growth charts to plot weight for length is recommended (http://www.cdc.gov/growthcharts/). “When using the WHO growth charts, values of 2 standard deviations above and below the median, labeled as the 2nd and 98th percentiles on the growth charts, are recommended for identification of children whose growth might be indicative of adverse health conditions.” The rationale for use of the WHO growth charts for this age group includes the following: (1) the recognition that breast-feeding is the recommended standard for infant feeding and, unlike the CDC charts, the WHO charts reflect growth patterns among children who were predominantly breast-fed for at least 4 months and still breast-feeding at age 12 months; (2) clinicians already use growth charts as a standard for normal growth; and (3) the WHO charts are based on a high-quality study, the multicenter growth reference study (MGRS).¹⁸

The incidence of childhood obesity is due to complex interactions between genetics and the environment.^19,20 The etiology is usually multifactorial, and it is important to conduct a complete history and physical examination and a comprehensive assessment which includes a detailed review of the birth history, family history, social history, developmental history, physical activity and dietary history, history of medication use, and review of systems. The differential diagnosis centers on 4 main categories: genetic syndromes, endocrine causes, medications, and exogenous factors.

Genetic syndromes and single gene mutations associated with obesity

Genetic syndromes are rare, but it is important to be aware of the typical presentation of those syndromes most likely to be associated with obesity (eg, Prader-Willi, Bardet Biedl, Alstrom, Cohen) (Table 11-1).^21,22 Mutations in the melanocortin-4 receptor (MC4-R) also deserve mention as they are the most frequent monogenic cause of obesity in children.^{23, 24, 25} Though the treatment is similar to other children with obesity, being aware of a genetic cause can inform parents of the risk for future children and also provide context for the obesity diagnosis and follow-up of associated conditions associated with the genetic syndrome. Parents may also be reassured to know that there is a “cause” of their child’s condition. The more common genetic risk factor is a strong family history of obesity—as manifested by parental and sibling obesity. Parental obesity has been shown to be one of the strongest predictors of childhood obesity.^19,26 Though environment plays a key role (see Exogenous Causes), there are likely more subtle metabolic or genetic factors at play.

Endocrine causes of obesity

Childhood obesity can result from endocrine abnormalities. It is important to become familiar with the signs and symptoms of these conditions and be aware of features that suggest these etiologies when evaluating a child with obesity. Diagnoses include Cushing syndrome, growth hormone deficiency, hypothyroidism, insulinomas, hypothalamic obesity, and pseudohypoparathyroidism.²⁷ In addition to the typical signs and symptoms for these conditions, children with obesity and an endocrinopathy can also have developmental delay. Any child with obesity and short stature (2 standard deviations below the mean)⁷, linear growth deceleration especially when it is a departure from prior heights, and developmental delay should be evaluated for an endocrinopathy and merits a complete laboratory workup including assessment for a genetic etiology.

Medications

Because of the possible contribution of medications to the onset of obesity, the history should include a review of the patient’s current and prior medication use and whether there appears to be a temporal link between a specific medication exposure and their weight gain. Medications used in pediatrics that have the potential to promote weight gain include corticosteroids, antiepileptic drugs (eg, valproic acid, carbamazepine), psychotropic drugs (eg, lithium, selective serotonin reuptake inhibitors [SSRIs]), tricyclic antidepressants such as amitriptyline, nortriptyline, and imipramine, antipsychotics such as risperidone and monoamine oxidase inhibitors (MAOIs), and hormonal contraceptives (eg, Depo-Provera).^32,33 If there is a temporal relationship between the medication start and weight gain, the medication should be suspected. Certain medications, such as atypical antipsychotics, are associated with increased risk of insulin resistance and metabolic risk.³⁴ Documented weight gain on an atypical antipsychotic should lead to a thoughtful review of alternatives.

Exogenous causes

The child’s environment, including access to food and activity, is an important factor in the differential diagnosis of obesity in children. The family diet and the child’s access to activity may be the only modifiable causes of the weight gain. A thorough evaluation of these factors may be time consuming in primary care (see Assessing Weight-Related Behaviors next), but it is possible to ascertain common problems using readily available screening tools, and over the course of repeated visits, a full picture may be obtained.

Nutrition

The most accurate method for assessing a child’s food intake is a formal quantitative assessment of caloric intake through a food frequency questionnaire, food record, or detailed interview by a registered dietitian.³⁵ However, these methods are time consuming and few clinical settings have a dietitian on staff, or have the time to conduct such an assessment.² This type of detail is generally most appropriately reserved for research settings, or for cases in which less time intensive methods have failed.³⁶ Pediatric health care providers should instead do a brief nutrition assessment during office visits that includes nutrition content and eating behavior.^2,37 In fact, current guidelines recommend that all children receive some level of nutrition assessment at every checkup as part of standard of care. Children with obesity should have an expanded assessment.

The baseline nutrition assessment for a child with obesity should include both an evaluation of the dietary content and family and child eating patterns and behaviors. Given that the child’s eating patterns are linked to the family’s diet, the health care provider should assess the food intake for the whole family. Including the parents or guardian in the assessment sends the message from the beginning that their eating patterns directly impact their child.^1,2,38 Furthermore, interventions that focus on parenting skills and parental behavior change have been shown to be more effective in children with obesity.³⁸

Food and beverage recall

Given the demands of busy clinical practice, providers can choose between a longer nutrition assessment through a 24-hour recall (5-10 minutes) or a shorter assessment focusing on key health behaviors.¹ For the 24-hour recall, the interviewer asks the individual what he or she ate and drank in the past 24 hours in chronological order.³⁷ Families often need multiple prompts to report all the details. If there is extra time, it is helpful to ask whether the day before was typical and if not, ask for more typical intake. To save time in clinic, a written 24-hour food record form can be administered, but an in-person assessment is preferable because it opens up the dialogue around nutritional behaviors and problems.

It is helpful to guide the family through the day with prompts for each meal and specific questions directed at certain food groups. High-yield food areas to ask about include carbohydrates that are low in fiber such as rice, cereal, baked goods, chips, and snack foods; the variety and frequency of fruits and vegetables; and high fat or lean proteins. In addition, whether the food is prepared at home or purchased through school lunch or as fast food is also important. These are all well-known risk factors for weight gain and are therefore ideal targets for screening and counseling.¹

Brief written assessments usually focus on a small list of key factors, such as sugar-sweetened beverages (SSBs), fruits and vegetables, screen time, eating breakfast, fast food, family meals, and portions.¹ Several toolkits exist to aid in these brief assessments, such as the 5-2-1-0 Let’s Go! Campaign in Maine.³⁹

One of the most well-described and accepted risk factors for weight gain in children is the consumption of SSBs.⁴⁰ SSBs have been shown to have an independent association with future cardiometabolic risk.⁴¹ Interventions have shown that a reduction in SSB consumption can have a positive impact on weight status and ameliorate the negative health effects of obesity.^42,43 As part of the initial assessment of a child with obesity, the pediatric health care provider should ask in detail about beverage consumption. Using the model of the 24-hour recall discussed earlier, the provider should ask about all beverages consumed, specifically asking individually about water, milk, soda, juice, and sports drinks. In addition, the health care provider should get a sense of the quantity of SSBs consumed at each time.

Eating behavior

The final, and perhaps most essential, component of the nutrition assessment of a child with obesity is a thoughtful review of the family and child’s eating behavior habits. The child’s dietary intake is the result of entrenched eating behaviors that are often shared with the family. Eating behaviors refer to habits or routines that a patient and family have around eating and can be classified as healthy, unhealthy, and extreme (Table 11-2).⁴⁴ Healthy eating behaviors include eating meals prepared at home that are eaten together as a family at regular intervals. Family meals in particular have been associated with reduced obesity risk and a lower incidence of extreme eating behaviors among children who already have obesity.^45,46 The other important aspect of healthy eating is eating intuitively, which means that the child recognizes physiologic hunger and satiety cues and only eats when actually hungry.⁴⁷ Family and cultural norms around eating and food preparation can contribute either to healthy or unhealthy eating behaviors.