The Child with Increasing BMI: A Primer on Pediatric Obesity
After reading this article and answering the review questions, the reader will:
- Define overweight and obesity in the pediatric patient
- Manage obesity in children according to recommendations by the American Academy of Pediatrics (AAP)
- Recognize the complications of pediatric obesity
Jacob is a 10-year-old boy seen in your clinic with his mother for a well-child check. She is concerned that he has become more fatigued in the afternoons and has difficulty keeping up with teammates on the soccer field. He was last evaluated 18 months ago with complaints of wheezing with an upper respiratory infection. These symptoms have since resolved. At that time, his BMI was at the 89th percentile.
Besides mild wheezing with respiratory illnesses, Jacob has no significant past medical history. He has never required steroids for these illnesses and takes no medications on a regular basis. Jacob lives in a farming community with his parents and older sister. He is a fourth-grade student with average performance. He watches TV or uses the computer from 4pm until supper at 6pm while his parents do chores and prepare the meal. He does homework after supper.
When asked about his eating habits, Jacob states that he has breakfast with 2% milk at home at 6am before catching the school bus. He eats a second breakfast with juice at 7am at school. Morning snack is served at 9:30am and is usually a carbohydrate choice. He has school lunch and then a snack that consists of two Pop tarts and juice. He has a bowl of ice cream after supper.
Family history is significant for hypertension in his father, a history of gestational diabetes with both pregnancies in his mother, and type 2 diabetes in all grandparents.
On physical exam, Jacob's BMI is now at the 97th percentile. His blood pressure is at the 90th percentile for age and sex using an appropriately sized cuff. After walking down the clinic hall, his pulse is 103 bpm and respiratory rate is 25 breaths/min. Jacob is noted to have generalized adiposity. He has mild hyperpigmentation at the nape of his neck. Cardiac exam is normal except for tachycardia. Pulmonary exam reveals good air movement and clear breath sounds. He has pink abdominal striae bilaterally. The remainder of the physical exam appears normal.
After discussing the growth chart findings with Jacob's mother, she is concerned. You mention your suspicion that his increased BMI may be the cause of his decreased stamina and exercise tolerance. You make recommendations for addressing these problems.
Pediatric Obesity: The Scope of the Problem
Pediatric obesity has become an increasing problem in US pediatric and family medicine practices. In the 1960s, approximately 5% of American children were obese. The 2007-2008 National Health and Nutrition Examination Survey (NHANES) found that 16.9% of American children ages 2-19 years were obese. 1 In Wisconsin, 9% of high school students were identified as obese in 2009 through the Wisconsin Youth Risk Behavior Survey (WYRBS). Despite this increase in obesity, access to physical activity in schools has decreased. In fact, 45% of Wisconsin high school students reported not participating in gym class during the school week.2
Pediatric obesity is associated with risk factors for adult cardiovascular disease, such as dyslipidemia, hypertension, type 2 diabetes mellitus, and polycystic ovarian syndrome. Significant morbidity or mortality can also be related to other complications, which will be discussed further. Finally, one-third of overweight children and 75% to 85% of obese adolescents become obese adults. 3,4
Diagnosis of Pediatric Obesity
The accepted definition of pediatric obesity, endorsed by the AAP, is a body mass index (BMI) greater than or equal to the 95th percentile for age and sex.5 A subset of these patients, with a BMI greater than or equal to the 99th percentile for age and sex, are defined as severely obese. Severely obese children have the highest and earliest risk of developing complications from obesity.6 The obese adult is defined as having a BMI ³ 30 kg/m2. Adolescents who reach a BMI of 30 kg/m2 at the 95th percentile for age and sex then meet this adult criterion.
Numerous studies demonstrate a disproportionate risk for pediatric obesity in certain ethnic groups. Obesity affects as much as a quarter of African American girls. Higher rates are also seen in Asian American, Native American, and Hispanic American children. Unfortunately, there is also ethnic variation in risk of developing complications from obesity. For example, nonalcoholic fatty liver disease (NAFLD) occurs more commonly in Hispanic obese youth.7
"Pediatric overweight" has been defined as the condition which exists when a child has a BMI greater than the 84th percentile but less than 95th percentile for age and sex. Concern exists among practitioners about whether this group might include some very muscular children. In practice, history of activity and physical examination will usually allow the practitioner to discern whether a child has increased adiposity or muscle mass. In some select situations, use of dual energy x-ray absorptiometry (DEXA) scan technology to quantify fat versus muscle mass may be considered.8
Complications of Pediatric Obesity
Cardiovascular complications of pediatric obesity can be seen even in young children and include primarily hypertension and dyslipidemia. In fact, atherosclerotic plaques have been identified in children postmortem as young as 5 years.9 Hypertension should be treated promptly to avoid eventual left ventricular hypertrophy. Beginning at 2-10 years of age, obese children with a family history of dyslipidemia should have a fasting lipid panel obtained.
Pulmonary complications of pediatric obesity may initially appear as obstructive sleep apnea (OSA) with snoring or pauses in respiration during sleep. Since OSA may further decrease energy levels in children with obesity, the diagnosis should be sought and addressed with pulmonary and ENT consultation as needed. Other children with obesity may have a complaint of wheezing with exercise. It is unclear if these children have a higher incidence of asthma or whether the wheezing reflects deconditioning. Bronchodilator therapy may be beneficial in either case, and gradual increases in exercise times should be encouraged.
Orthopedic complications of pediatric obesity may include: flat feet, nonspecific knee, foot or back pain, avascular necrosis of the hip, slipped capital femoral epiphysis, and Legg Calve Perthes disease. The obese child with orthopedic complaints should not be removed from physical education class at school. Rather, consultation with a non-operative orthopedist (Dr. Blaise Nemeth at American Family Children's Hospital) or one of the other pediatric orthopedists at AFCH may be considered. Often these consultations can provide custom orthotics or bracing as well as recommendations for specific physical activity that can be undertaken while the orthopedic complaint is addressed. ENERGY IN = ENERGY OUT is an important concept to keep in mind when addressing orthopedic issues: if all physical activity is discontinued while the child consumes the same number of calories, weight gain will occur.
Gastrointestinal complications of pediatric obesity include diseases classically considered to be adult conditions. NAFLD is being recognized with increased frequency in obese youth. It can range from mild hepatitis to cirrhosis and increases a patient's risk for hepatocellular carcinoma.10 NAFLD may be present for a prolonged period before liver transaminases become abnormal, necessitating another marker for earlier identification. Gallstones may be seen in children before or after weight loss and should be considered in children with persistent or recurrent upper abdominal pain. Gastroesophageal reflux is also frequently described.
Endocrine complications of obesity in children include: impaired fasting glucose, impaired glucose tolerance, insulin resistance, and ultimately type 2 diabetes mellitus. Current American Diabetes Association (ADA) guidelines recommend screening asymptomatic overweight children who are at least 10 years of age or postpubertal for type 2 diabetes mellitus if they have at least two risk factors. Risk factors include: a positive family history of diabetes mellititus, susceptible ethnicity, hypertension, dyslipidemia, acanthosis nigricans, and polycystic ovarian disease. Screening consists of a fasting glucose, oral glucose tolerance test, and possibly the HGbA1c test. Diagnosis of diabetes in the absence of classical symptoms (polydipsia, polyuria, polyphagia) requires abnormalities on two separate testing events.11
Reproductive complications of pediatric obesity may become manifest in the premenarchal, perimenarchal, or postmenarchal period. Obese elementary age girls may experience premature adrenarche and may, on average, experience menarche a year earlier than age-matched non-obese peers.12,13 A later complication may include polycystic ovarian syndrome and appear as the emergence of hirsutism, severe acne, primary or secondary amenorrhea, oligomenorrhea, or menorrhagia.13
Renal complications of pediatric obesity have increased over the last decade and include proteinuria, focal segmental glomerulosclerosis, and diabetic nephropathy. In order to identify renal disease in an early stage in obese patients, practitioners should obtain annual urinalyses and measure blood pressure at every clinic encounter.14
Psychosocial complications of obesity include depression, poor self-esteem, and social phobias. These complications as well as comorbid psychiatric conditions, such as anxiety or depression, can impair an obese child's ability to improve his or her BMI by making sustained behavioral changes more difficult. Consultation with psychologists or psychiatrists may be indicated.
Prevention of Obesity in Young Children
Prevention of childhood obesity begins with the prenatal visit. Practitioners should give anticipatory guidance regarding normal weight gain and growth in infancy and toddlerhood. Parents should be discouraged from regarding weight gain as a developmental milestone. "Slim" infants and toddlers should be accepted as normal as long as linear growth proceeds normally. Furthermore, rapid "catch-up" weight gain in small-for-gestational-age infants is no longer advisable. Breast-feeding should be encouraged for at least six months of infancy, as breastfed babies are less likely to become obese children. Juice should be discouraged as a calorie source.
Management of Pediatric Obesity
The goal of initiation of dietary change in an obese child is gradual improvement of BMI, prevention of obesity-related complications, and normal linear growth velocity. Families should be encouraged to eat together at the dinner table. This recommendation often requires creativity and rearrangement of mealtime in working families. Portion size education is necessary, and the use of smaller plates can facilitate this change. Children should not be allowed to skip meals, particularly breakfast, as skipping increases hunger and binge eating later. Half the plate at mealtimes should consist of fruit and vegetable portions, a quarter protein, and a quarter bread or pasta. Juice should be eliminated from the diet. If any is consumed, juice should be limited to 8 ounces or less per day in older children and 4 ounces or less in preschool children and toddlers. Regular sodas and energy drinks should be eliminated from the diet. Stepwise transition to skim milk is recommended, with water or skim milk being the beverage of choice for mealtimes. Concerns about vitamin intake can be alleviated with a daily multivitamin.
The expertise of pediatric dieticians can assist practitioners in educating families about nutrition. The goal of dietary change is to allow an overweight or obese child to grow in height without gaining weight. In children with open epiphyses, actual weight loss is generally only recommended if the BMI is greater than the 99th percentile unless severe obesity complications are present at a lower BMI. An example of a child needing to lose weight is a hypertensive child with BMI greater than the 96th percentile and type 2 diabetes. Importantly, adequate calcium and vitamin intake must be maintained at all caloric recommendations.
Movement, Movement, Movement
The AAP recommends 60 minutes of vigorous physical activity per day for prevention of obesity.15 For a younger child, this should consist of play. Some families may need to teach their children how to actively play, as television and computer time often occupy even the young child's day. The main concept to reinforce is to keep the child moving and weight-bearing as much as possible.
For an obese older child or adolescent, even 150 minutes per week may initially seem an unreachable goal. Some patients become dyspneic walking to the exam room. Recommend reachable interval goals. Perhaps at first just 10 minutes of exercise per day may be attainable. This amount can be gradually increased as tolerated. Exercise and movement do not necessitate joining a sports team. On the contrary, while having many potential social and emotional benefits, teams may not offer a child as much sustained physical activity as compared to an individual activity in which he is the continuous participant. Examples of beneficial continuous activities include walking, swimming, weightlifting, or dancing. Increasing "energy of daily living" utilization can be accomplished by walking to nearby destinations within a half-mile radius and using stairs whenever available. Families can also be encouraged to choose open spaces in parking lots as far from businesses as possible, to increase walking time while running family errands.
Medications are not recommended for routine management of childhood obesity. The only medication for treating pediatric obesity currently approved by the FDA is orlistat.16 Orlistat causes modest weight loss by inhibiting intestinal lipase, leading to fat malabsorption. It is approved for use in adolescents age 12 years or greater. However, its use is limited secondary to a common side effect of stool leakage, particularly if a fatty food is ingested. If used, orlistat may subsequently lead to deficiencies of the fat-soluble vitamins and occasionally serious drug-induced hepatitis. Laboratory studies to monitor for these complications must be obtained regularly.17
Successful management of the obese pediatric patient requires a commitment by the patient, family, and healthcare team to diet, physical activity, and lifestyle modification. For the severely obese patient, additional consultation with a multidisciplinary clinic such as the UW Pediatric Fitness Clinic may offer further support. The Fitness Clinic provides a management plan specific for each child and includes 1) an exercise prescription developed by an athletic trainer, 2) dietary guidelines provided by a pediatric dietician, and 3) additional consultation by an endocrinologist, family practitioner, or sports medicine physician who specializes in pediatric weight management. Such consultation may augment the practitioner's recommendations for the family. Children with obesity should be reassessed at frequent intervals by their practitioner for progress in BMI improvement and prevention of obesity-related complications.15
Overweight and obese children are seen with increasing frequency in pediatric and family practices. The AAP has joined Michelle Obama in the "Let's Move" initiative to address childhood obesity. This group jointly recommends plotting BMI, addressing good nutrition, and prescribing exercise to encourage physical activity at every well child visit.18 Screening for and treating complications of obesity in childhood may prevent or delay adult atherosclerotic disease and should be a goal of every practitioner.
- Ogden CL, Carroll MD, Curtin LR, Lamb MM, Flegal KM. Prevalence of high body mass index in US children and adolescents, 2007-2008. JAMA. 2010;303(3):242-9
- Merritt RJ. Obesity. Curr Probl Pediatr. 1982;12:1-58
- Stark O, Atkins E, Wolff OH, Douglas JW. Longitudinal study of obesity in adulthood from body mass index values in childhood and adolescence. Am J Clin Nutr. 2002;76:653-8
- Krebs NF, Himes JH, Jacobson D, Nicklas TA, Guilday P, Styne D. Assessment of child and adolescent overweight and obesity. Pediatr. 2007;120(4):S193-228
- Barlow SE. Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediatr. 2007;120(4):S164-92
- Roberts EA. Non-alcoholic steatohepatitis in children. Clin Liver Dis. 2006;11(1):155-72
- Goulding A, Gold E, Cannan R, Taylor RW, Williams S, Lewis-Barned NJ. DEXA supports the use of BMI as a measure of fatness in young girls. Int J Obes Relat Metab Disord. 1996;20(11):1014-21
- Berenson GS, et al. Atherosclerosis of the aorta and coronary arteries and cardiovascular risk factors in persons aged 6 to 30 years and studied at necropsy (The Bogalusa Heart Study). Am J Cardiol. 1992;70:851-8
- Alisi A, Manco M, Vania A, Nobili V. Pediatric nonalcoholic fatty liver disease in 2009. J Pediatr. 2009;155(4):469-474
- American Diabetes Association. Standards of medical care in diabetes - 2010. Diabetes Care. 2010;33(S1):S11-61
- Frontini MG, Srinivasan S, Berenson GS. Longitudinal changes in risk variables underlying metabolic syndrome X from childhood to young adulthood in female subjects with a history of early menarche: the Bogalusa Heart Study. Int J of Obesity. 2003;27:1398-1404
- Ibanez L, DiMartino-Nardi J, Potau N, Saenger P. Premature adrenarche - normal variant or forerunner of adult disease? Endocr Rev. 2000;21(6):671-96
- Adelman RD, Restaino IG, Alon US, Blowey DL. Proteinuria and focal segmental glomerulosclerosis in severely obese adolescents. J Pediatr. 2001;138(4):481-5
- Spear BA, Barlow SE, Ervin C, Ludwig DS, Saelens BE, Schetzina KE, Taveras EM. Recommendations for treatment of child and adolescent overweight and obesity. Pediatr. 2007;120(4):S254-88
- August GP, et al. Prevention and treatment of pediatric obesity: an Endocrine Society clinical practice guideline based on expert opinion. J Clin Endocrin Metab. 2008;93(12):4576-99