The incidence of childhood obesity is on the rise, with recent data from the Centers for Disease Control and Prevention suggesting that 12%-18% of children aged 2-19 years are considered obese. This represents a three- to sixfold increase in the prevalence of pediatric obesity since the 1970s.
Obesity has clear complications and comorbidities, including increased risk of type 2 diabetes, asthma, and nonalcoholic fatty liver disease, as well as an increased risk of adverse psychological issues such as depression. Characteristics that increase the risk for pediatric obesity include male gender, advancing age (adolescents are at high risk), and minority status.
In 2005, the U.S. Preventive Services Task Force released a recommendation statement promoting the use of body mass index (BMI) as a suitable screening method for obesity in the pediatric population. Recently, the USPSTF released an updated statement on pediatric obesity with a stronger focus on treatment and outcomes.
Screening
Screening for overweight and obese children should be performed utilizing BMI, which is calculated as weight in kilograms divided by height in meters squared. This is a grade “B” recommendation, meaning that there is a moderate degree of certainty that the net benefit is moderate. The BMI is then plotted on growth charts against gender- and age-specific norms. These growth charts were published by the CDC in 2000 and were formulated with data from multiple national health examination surveys spanning 3 decades.
In the pediatric population, “overweight” is defined as BMI in the 85th-94th percentiles; “obese” is defined as a BMI of at least the 95th percentile, as plotted for age and sex, based on data collected from 1963 to 1995.
Although the USPSTF found moderate evidence to utilize BMI an acceptable screening method for obesity, it did not find adequate evidence to recommend screening timing and intervals other than routine measurements performed at regularly scheduled health maintenance visits. The USPSTF also found sufficient evidence to recommend initiation of screening for obesity beginning at 6 years of age.
Behavioral Treatment
On review of thirteen trials including more than 1,200 children and adolescents aged 4-18 years, the USPSTF found moderate evidence that identification of an obese pediatric patient via BMI screening with subsequent referral to a moderate- to high-intensity intervention at a specialty health care center resulted in modest weight loss over 12 months; these programs were defined as providing at least 25 hours of contact between the child and/or family and the health care center over a 6-month period. Very low or low-intensity programs (defined as less than 25 hours of patient to health professional interaction over a 6-month period) were not found to be statistically significant in terms of weight loss.
Interventions were deemed comprehensive if they included the following characteristics: weight loss/diet counseling, physical activity counseling, behavior management instruction, and sustained support regarding new diet and exercise changes. Behavioral management often included cognitive behavioral therapy in reference to self-monitoring, impulse control, and triggers for overeating/poor food choices.
Examples of moderate weight loss in a 16-year-old were, on average, 19 pounds for a female and 22-23 pounds for a male.
There was limited evidence that moderate- to high-intensity programs yielded improvements in insulin resistance in pediatric patients. However, there was not a consistent reduction in other cardiovascular risk factors, including blood pressure or cholesterol levels.
Pharmacologic Treatment
Two medications are FDA-approved for weight reduction in the adolescent population. Orlistat is a pancreatic lipase inhibitor and is approved for children 12 years and older; sibutramine is a centrally acting appetite suppressant and serotonin reuptake inhibitor approved for adolescents 16 years and older. Small but significant improvements in BMI were found when these medications were used in conjunction with behavioral interventions.
While the addition of either of the two medications did not appear to affect growth or mental health, gastrointestinal side effects – such as abdominal cramping, flatus, or oily spotting – were common and found in about 30% of the patient population, particularly with sibutramine. Sibutramine also has been associated with an increase in blood pressure and heart rate, with recent questionable links to increased cardiovascular events in the adult population. Cardiovascular effects in the pediatric population are unknown. Data also are lacking regarding weight maintenance in the pediatric population after discontinuation of these medications.
Limitations
The USPSTF statement did not address children younger than 6 years of age. In addition, the effects of intensive behavioral interventions on overweight children – but not obese children – have not been carefully studied. Further limitations include a need for more information on appropriate obesity interventions for low-income children.