The first step in the evaluation of the obese child or adolescent is determining the height and weight and calculating the body mass index (BMI) (1). Data for the current BMI curves represent cross-sectional data from the U.S. population collected between 1963 and 1980. BMI is highly correlated with increased adiposity in children and adolescents with BMI greater than the 85th percentile for age and gender (2).
The Centers for Disease Control and Prevention (CDC) considers children and adolescents whose BMI is between the 85th and 95th percentiles to be “at risk for overweight,” and children and adolescents with a BMI greater than the 95th percentile are considered to be “overweight” (1). There is growing consensus for using the term obesity to describe children whose BMI is greater than the 95th percentile and overweight to describe children whose BMI is between the 85th and 95th percentiles (3) to more clearly indicate the risk of having a BMI greater than the 95th percentile in terms of obesity-related comorbidities.
BMI is calculated as weight (kg)/height (m2) or weight (lb)/height (in.2) ÷ 703. The result is plotted against age on a gender-specific BMI curve (Figs. 5.1 and 5.2).
BMI will help identify children who are obese (BMI >95th percentile), overweight (BMI between the 85th and 95th percentiles), normal weight (BMI between the 5th and 85th percentiles), or underweight (BMI <5th percentile for age and gender). When applied to an individual child, the calculation of BMI allows for classification and prompts further evaluation of individual risk factors for obesity and obesity-related comorbidities. If a child is younger than 2 years, then length-for-height measurements are plotted (Figs. 5.3 and 5.4).
Patterns of weight and BMI change can also be very informative. Children or adolescents who are crossing percentiles are at risk for continued weight gain (1), and a thorough evaluation of activity, inactivity, and nutritional habits would be indicated.
FIG. 5.1. Body mass index-for-age percentiles: boys 2 to 20 years. (Developed by the National Center for Health Statistics in collaboration with the National Center for Chronic Disease.)
FIG. 5.2. Body mass index-for-age percentiles: girls 2 to 20 years. (Developed by the National Center for Health Statistics in collaboration with the National Center for Chronic Disease.)
FIG. 5.3. Weight-for-length percentiles: girls birth to 36 months. (Developed by the National Center for Health Statistics in collaboration with the National Center for Chronic Disease.)
FIG. 5.4. Weight-for-length percentiles: boys birth to 36 months. (Developed by the National Center for Health Statistics in collaboration with the National Center for Chronic Disease.)
In addition, weight gain may often accompany stressful situations in a young person's life, such as the following:
Examining the child's situation at the time weight gain occurred may give direction to the kind of intervention required to regain energy balance.
Once a child is found to have a BMI greater than the 95th percentile, the physician must screen for obesity-related risk of disease. Then the child's or adolescent's nutrition, activity, and inactivity patterns should be assessed to determine the potential for change as it involves the child, the family, and the environment. Families should be engaged in a dialogue about value for change, prioritization of needed changes, and strategies for family-based change to begin helping the child achieve a healthier weight (1).
Assessment of Obesity-Related Comorbidities
The remainder of this book addresses obesity-related comorbidities in detail. Table 5.1 presents those comorbidities that need to be assessed when the clinician has determined that a child is overweight or obese.
Fasting glucose, insulin, lipid profile, and liver enzyme tests have been recommended in children with a BMI greater than the 95th percentile (1). Other laboratory
testing is based on clinical evaluation, family history, and signs and/or symptoms of comorbid conditions.
TABLE 5.1. Obesity-related comorbidities
Assessment and Treatment of Energy Imbalance
Obesity is an excess of adipose tissue, created and maintained by an ongoing mismatch between energy intake and energy utilization.
In addition to determining the growth pattern of height, weight, and BMI over time, it is important to identify the sources of the energy imbalance and the possible areas where this imbalance can be corrected. To do so, energy intake and energy output need to be assessed, as well as factors that may encourage or impede lifestyle changes that need to occur. Numerous guidelines suggesting a balanced approach to preventing and treating obesity have been published (1,5,6,7).
In the nutritional assessment, imbalance of nutrients, portion size, sugar-sweetened beverages, fast food, and frequent snacking are common findings in the diets of overweight youngsters.
A detailed dietary history is essential.
Asking the child to begin in the morning and go through his or her day will give the pediatrician a good working idea of nutritional factors that are in need of change. For example, a typical 1-day dietary history for an obese adolescent might show that breakfast was skipped, lunch was a soft pretzel and juice, and the after school snack consisted of a bag of chips and soda purchased at the local store. Dinner might be pizza eaten out with the family, and snack food with soda might comprise the night-time eating. At this point, more than enough information has been given to begin the process of change.
Consumption of sugar-sweetened beverages has been linked to obesity (8). In a prospective study that eliminated sugar-sweetened beverages, adolescents in the upper one third of the BMI range had significant decreases in BMI compared with similar adolescents who drank sugar-sweetened beverages (9).
One of the potential contributors to energy imbalance has been the increase in portion size (10). If children are offered larger portions, they will eat more food (11). Consumption of fast food is another factor in increasing energy imbalance. A large household survey revealed that one third of children eat fast food every day. Consumption of fast food was associated with a caloric increase of 187 kcal/day and
a diet that included greater amounts of fat, carbohydrate, sugar, and sugar-sweetened beverages and reduced intake of fiber, fruits, and vegetables (12). Increasing fruit, vegetable (13), and dairy consumption (14) has been associated with improved energy balance.
It is always important to identify the nutritional environments the child is exposed to during the day or week. Parents may not know what meals and snacks day care may be providing, and need to be encouraged to ask for menus. Many schools are trying to improve the nutritional quality of their breakfast and lunch programs; however, the meals in some schools are still problematic and a packed lunch would be an improvement. By the same token, vending machines may be filled with soda and unhealthy snacks or with water and fruit, depending on the school, and parents need to be aware of their child's nutritional exposure.
It can no longer be assumed that children will have enough activity in their day to keep them in energy balance.
As in a nutritional review, a review of daily and weekly activities is essential. Decreasing sedentary behavior in children has been associated with improvement in weight status (15).
The number of hours of television time has been associated with obesity (16) and a reduction in television time with reduced obesity (17). Asking the family and child about television, computer, and game and movie time will give an estimate of total “screen” time. The number and type of food advertisements on television has been linked to childhood risk of overweight both in the United States and in Europe (18). In addition, the presence of a television in the child's bedroom is a risk factor for obesity (19).
Outdoor time is also a measure of total activity; many children do not go outdoors during the week except for recess at school. Recess and physical education at school are activity opportunities, but many times children are not moving during the entire session. Issues such as community access to playgrounds, safety, cost, and transportation to sports activities may all be limiting factors for children and families. Family activities also play an important role in either limiting or encouraging a child to become active. Inquiring into these leisure pastimes will help in evaluating opportunities for change.
Also important are any medical or physical limitations a child may have to increasing physical activity. Conditions such as asthma and deconditioning are common reasons children and parents may limit activity. Sleep apnea presenting as daytime tiredness may also interfere with activity during the day. Motor deficits and developmental delay can present special challenges as families work to increase activity. Children who are depressed or anxious often may be reluctant to participate in peer activities and need help and encouragement to change activity patterns.
Family, Psychosocial, and Environmental Assessment
Family-based change is key in helping the child or adolescent attain a healthy weight. Family members are asked to “buy into” lifestyle change. Providing necessary information about obesity with its related comorbidities and recommending treatment and options for lifestyle change are important elements of intervention. Stepwise implementation of change with support for setbacks, is vital in helping families learn how to manage risk factors.
In addition to working together, families must be able to assess the nutritional and activity environment both inside and outside the home. They must learn to pay attention to day care and school menus, snacks, and activity opportunities offered at school and after school. Moreover, eating out at restaurants and in other social settings needs to be addressed. For families and children to accomplish lifestyle change, they will need to develop the decision-making skills necessary to functional optimally in their nutrition and activity environment.
Temperament, parenting style, and family interactions may all influence the family's ability to manage healthy nutrition and activity for the child. Helping families work through behavioral issues, which may arise during treatment, enables the process of change.
Focusing on healthier eating and supporting family-based change are more helpful than calorie counting. There are families, however, who want a more structured nutritional plan, and referral to a dietitian can be helpful.
In any plan to address obesity in a child, ongoing support from extended family and physician is crucial. Although the overall goal is return to a healthy weight and energy balance along with resolution of obesity-related comorbidities, goals are tailored to the child's needs and are incremental to allow for success at implementation. Examples of goals are listed in Table 5.2.
Family-Based Lifestyle Change
There are several keys to helping the family make lifestyle change (1):
TABLE 5.2. Examples of goals to address in childhood obesity
SB is a 6-year-old girl you have cared for in your practice since she was an infant. It is time for her yearly well check. When you see SB's growth chart, plotted by your nurse, you notice that she has crossed from the 75th percentile in weight, which she had been steadily following, and is now in the 90th. Her height is still at the 75th percentile and is nicely following the curve. Her weight is now 56 lb (90th percentile) and her height is 47 in. (75th percentile), with a BMI at the 91st percentile. Her blood pressure is 98/53 mm Hg.
You begin by asking her mother how the family has been over the past year since you have seen them. The mother initially says fine but looks upset, and you ask if anything is wrong. She nods and says that she and her husband have just separated and “things have been rough for a while.” You express sympathy and ask with whom SB and her brother are living, and the mother says that the children live with her and they see their father one evening a week and every other weekend.
You ask Mrs. B if she has any specific health or behavior concerns about SB, and she says she has been worried about SB's self-esteem. You ask how she became concerned about this, and the mother says that SB has been making negative remarks about herself and her “belly being too big.” She also suspects that SB may be getting teased at school. You ask Mrs. B if she has noticed any change in SB's eating or activity level, and she says that SB seems to be hungry a lot and has refused to join the soccer team she played for last year.
You go over the growth chart with Mrs. B and mention that the family could be eating healthier and getting more activity. Mrs. B agrees.
Then you obtain a dietary history from SB. She is eating cereal and milk for breakfast, and her mother is packing her lunch, which consists of a sandwich, fruit,
and pretzels. It turns out that SB frequently is trading her pretzels for chips, and her friends may also give her extra snacks from their lunch. In the after school program, SB has juice and crackers for a snack. When she arrives home, her mother cooks dinner, but her mother notes that SB is continuously asking for food and sometimes will sneak food if she is not given something to eat. Both children are drinking juice between meals; the mother does not buy soda, but SB says there is soda at her father's home.
When asked to estimate the amount of screen time SB has, the mother says about 3 hours, mostly television. She does not know how much television time SB has at her father's house.
You review the family history, which is positive for diabetes in a maternal grandmother and cardiovascular disease in a paternal grandfather. SB's review of systems is essentially normal. On physical examination, the only finding, in addition to a BMI at the 91st percentile, is slightly enlarged tonsils.
You ask the mother if she feels ready to make changes in the family's eating and activity. She says she would like to start. You review some of the possibilities, which include decreasing or eliminating juice, reducing television time, and working with SB to distract her when she is hungry. The mother thinks she can decrease the juice intake and try to distract SB but does not think she can work on the television watching. You start by having the mother try not to buy juice for the household and work with SB on other activities she can do when she feels hungry. You ask the mother to document any juice drinking and to come up with a list of activities for SB, with the goal of stabilizing SB's weight until her next visit in 1 month.
One month later, SB and her mother return. SB has not gained any weight. The mother reports that not only is she not drinking juice but also she has stopped trading food with her friends at school. The mother notes that SB has made fewer negative comments about herself and has seemed less hungry. You encourage SB and her mother to continue the good job they are doing and ask if there is anything else they would like to change. The mother notes that she would like both SB and her brother to watch less television, and you help the mother figure out how she could accomplish this. You have the mother call to check in with SB's weight in 1 month and schedule a revisit in 2 months. You let the mother know that you would be happy to see Mr. B if she wants him to come to the next appointment.