Screening for Obesity in Children and Adolescents
Since the 1970s, childhood and adolescent obesity has increased three- to six-fold. Approximately 12% to 18% of 2- to 19-year-old children and adolescents are obese (defined as having an age- and gender-specific body mass index (BMI) at =95th percentile). BMI values are used to determine a percentile score on the basis of population-based references such as those developed by the Centers for Disease Control and Prevention (CDC).
In January 2010, the U.S. Preventive Services Task Force (USPSTF) used the following terms to define categories of increased BMI: Overweight is defined as an age- and gender-specific BMI between the 85th and 95th percentiles, and obesity is defined as an age– and gender-specific BMI at =95th percentile. The USPSTF did not find sufficient evidence for screening children younger than 6 years.
Screening Tests
In 2005, The USPSTF found adequate evidence that BMI was an acceptable measure for identifying children and adolescents with excess weight. BMI is calculated from the measured weight and height of an individual.
Treatment
The USPSTF found that effective comprehensive weight-management programs incorporated counseling and other interventions that targeted diet and physical activity. Interventions also included behavioral management techniques to assist in behavior change. Interventions that focused on younger children incorporated parental involvement as a component.
Moderate- to high-intensity programs involved >25 hours of contact with the child and/or the family over a 6-month period and showed results including improved weight status, defined as an absolute and/or relative decrease in the BMI 12 months after the beginning of the intervention. Most participants were obese, and it is not known whether these results can be applied to children who are overweight but not obese. In addition, evidence was limited on the long-term sustainability of BMI changes achieved through behavioral interventions and on the trajectory of weight gain in children and adolescents. Interventions generally took place in referral settings, and the results can only be generalized to children who follow through on treatment. Low-intensity interventions, defined as =25 contact hours over a 6-month period, did not result in significant improvement in weight status.
Interventions that combined pharmacologic agents (sibutramine or orlistat) with behavioral interventions resulted in modest short-term improvement in weight status in children aged 12 years and older. There were no long-term data on the maintenance of improvement after discontinuation of medications. The magnitude of the harms of these drugs in children could not be estimated with certainty. Adverse effects included elevated heart rate, elevated blood pressure, and adverse gastrointestinal effects. Sibutramine, a centrally acting appetite suppressant, has been approved by the US Food and Drug Administration (FDA) for use in adolescents aged 16 years and older. Orlistat, a lipase inhibitor, has been approved by the FDA for use in adolescents aged 12 years and older. Neither sibutramine nor orlistat has been approved for use in pediatric populations younger than 12 years.
Screening Intervals
No evidence was found regarding appropriate intervals for screening. Height and weight, from which BMI is calculated, are routinely measured during health maintenance visits.
Burden of Disease
During the past 3 decades, childhood and adolescent obesity (defined as age- and gender-specific BMI at =95th percentile) has increased three- to sixfold, with the rate of increase dependent on age, gender, and ethnicity. Recent prevalence figures (2003-2006) have indicated that ~12% to 18% of 2- to 19-year-old children and adolescents are obese. The prevalence of obesity varies with age and is more likely to be higher in older children, in males, and in racial and ethnic minorities. Evidence suggests that childhood and adolescent obesity can have a sizeable health impact. Obese children and adolescents have an increased risk of type 2 diabetes mellitus, asthma, and nonalcoholic fatty liver disease; are more likely to have cardiovascular risk factors; and have greater anesthesia risk. They may also experience more mental health and psychological issues such as depression and low self-esteem compared with
non-obese children.
Behavioral Interventions
Thirteen behavioral intervention trials conducted with 1258 overweight or obese (primarily obese) children and adolescents aged 4 to 18 years were included in the USPSTF review. No studies targeted those younger than 4 years.
Hours of contact were used as a proxy for treatment intensity and categorized as very low (<10 hours), low (10-25 hours), moderate (26-75 hours), or high (>75 hours). Weight outcomes were defined as short-term (6-12 months since the beginning of the intervention) or maintenance (between 1 and 4 years after the beginning of the intervention and at least 12 months after the end of the intervention).15
The comprehensiveness of interventions was also assessed. Interventions were deemed comprehensive if they included all of the following elements: (1) counseling for weight loss or healthy diet; (2) counseling for physical activity or a physical activity program; and (3) instruction in and support for the use of behavioral management techniques to help make and sustain changes in diet and physical activity. Behavioral management techniques included self-monitoring, stimulus control, eating management, contingency management, and cognitive-behavioral techniques.15
Moderate- to high-intensity interventions were conducted in specialty health care facilities such as pediatric obesity referral clinics or similar settings. Such interventions would not be feasible for implementation in a primary care setting; however, they would be feasible for referral. The amount of absolute or relative weight change associated with 3 fair-quality comprehensive moderate- to high-intensity behavioral interventions was modest (1.9-3.3 kg/m2 difference in mean BMI 6-12 months after starting treatment, compared with controls). For an 8-year-old boy or girl, the largest BMI difference (3.3 kg/m2) would be equivalent to ~13 lb (based on 50th percentile for height for ages 8 and 9, assuming ~2 in of growth). For girls aged 16 years this BMI difference would be equivalent to ~19 lb, whereas for boys aged 16 years the difference would be between 22 and 23 lb. Limited evidence suggests that these improvements can be maintained over 12 months after treatment. Lower-intensity interventions that are possibly feasible for primary care did not demonstrate a significant, consistent benefit with regard to BMI. Limited evidence suggests that reductions in insulin-resistance measures are possible with moderate- to high-intensity comprehensive interventions. However, decreases in cardiovascular risk factors (e.g., blood pressure, lipid levels, blood glucose levels, or insulin resistance) were not consistent.
In 2007, an American Medical Association (AMA) expert committee of 15 individuals representing 15 professional medical organizations revised 1998 recommendations on how clinicians should approach the prevention, assessment, and treatment of childhood obesity. In the updated recommendations, the AMA advised that a clinician's assessment should include a BMI calculation as well as medical and behavioral risks for obesity. For overweight and obese patients, the expert committee proposed using a stepwise approach that divides treatment into several stages including counseling, providing a structured weight-management plan, and using a comprehensive multidisciplinary intervention/tertiary care intervention delivered by multidisciplinary teams with expertise in childhood obesity. The American Academy of Pediatrics endorsed the 2007 AMA expert committee recommendations and has also recommended the annual plotting of BMI for all patients aged 2 years and older.