Percentage of high school students with obesity, 2017
Childhood obesity is a major public health problem that continues to worsen despite intensive clinical and public health measures. It is a multifactorial condition with both genetic and environmental causes that is difficult to treat and puts patients at risk for lifelong comorbidities. Obesity is a chronic disease that requires frequent office visits, reinforcement, and encouragement for both the patient and family.
Body mass index (BMI) is the accepted measure for determining obesity in children aged two years and older. BMI is calculated by body weight (in kilograms) divided by height (in meters) squared. BMI calculators also take into account the age and sex of the patient. Weight categories are defined by percentiles.
- Underweight: <5th percentile
- Normal or healthy weight: 5th to <85th percentile
- Overweight: 85th to <95th percentile
- Obese: ≥95th percentile
A newer classification system divides obesity into further subcategories (from least to most severe):
- Class I: BMI ≥95th percentile
- Class II: BMI ≥120% of 95th percentile
- Class III: BMI ≥140% of 95th percentile
Based on the 2015-16 National Health and Nutrition Examination Survey (NHANES), 18.5% of children and adolescents in the United States are obese. The prevalence varies by age, ethnicity, and socioeconomic status. The rates are disproportionately high among Hispanics, African Americans, and those of low socioeconomic status.
Rates of obesity by age group:
- 13.9% among 2-5 year olds
- 18.4% among 6-11 year olds
- 20.6% among 12-19 year olds
Rates of obesity by ethnicity:
- 25.8% among Hispanics
- 22.0% among non-Hispanic blacks
- 14.1% among non-Hispanic whites
- 11.0% among Asians
Rates of childhood obesity are inversely related to the level of education attained by the household head. The prevalence of obesity in the highest income bracket is about half the prevalence within the low and middle income brackets.
Analysis of the 2016 NHANES data shows a persistent upward trend in prevalence.
Childhood obesity is a major risk factor for obesity in adulthood. The predictive value is related to age (obesity in older children and adolescents is more strongly associated with obesity in adulthood), family history of obesity, severity of obesity, and BMI trajectory.
Etiology of Obesity
- Environmental factors
- Excessive caloric intake
- Sedentary lifestyle
- Sugary drinks
- Amount of time spent watching television and playing video games
- Inadequate sleep
- Medications, including antipsychotics, antiepileptics, and steroids
- Genetic factors
- Genes thought to be responsible for 40 to 85% of variability of fat tissue between people but not well understood
- Albright hereditary osteodystrophy (pseudohypoparathyroidism)
- Medical conditions
- Cortisol excess, eg Cushing's syndrome
- Growth hormone deficiency
- Eating disorder
Complications of Obesity
- Premature atherosclerotic disease
- Type 2 diabetes
- Metabolic syndrome
- Polycystic ovarian syndrome
- Premature puberty
- Obstructive sleep apnea
- Nonalcoholic fatty liver disease
- Pseudotumor cerebri
- Slipped capital femoral epiphysis
- Genu varus (Blount disease) and valgus
- Vitamin D deficiency
- Iron deficiency
- Acanthosis nigricans
These conditions have been estimated to place a greater than $100 billion burden upon the medical and insurance systems annually in the United States alone.
Questions to ask parents and patients
Unfortunately, no good screening tool exists to identify children at risk for becoming obese. Instead, active surveillance using CDC growth charts remains the mainstay for identifying early obesity as childhood obesity is the strongest predictor of later obesity.
Regular high-calorie foods can easily cause weight gain given their high sugar, fat and calories.
Children who do not regularly exercise are more likely to gain weight due to decreased caloric expenditure. Leisure activities such as television or video games, contribute to the problem.
A family history of being overweight increases the likelihood of putting on excess weight, especially in an environment where high-calorie food is always available, and physical activity is not encouraged.
Some children overeat to cope with problems or to deal with emotions, such as stress, or to fight boredom.
Overreliance on convenience foods can contribute to weight gain. Controlling your access to high-calorie foods may help weight loss.
Children from low-income backgrounds are at greater risk of becoming obese as it takes both time and resources to make healthy eating and exercise a family priority.
General Treatment Guidelines and Goals
- Intervention should begin early. The risk of adult obesity increases with the child's age. Adolescent changes are quite difficult.
- Overcome the child's feeling of embarrassment and involve the child in conversations.
- Acknowledge that obesity is a chronic disease that requires treatment. Emphasize the medical complications and risks.
- Establish readiness and desire to institute change.
- Involve outside caregivers such as grandparents, babysitters, daycare facilities.
- Set SMART goals that are Specific, Measurable, Attainable, Realistic, and Timely. Examples are minor adjustments in food intake and exercise and eliminating empty calories such as soda and juice.
- Emphasize that this is a long-term plan and involves lifestyle changes. Other family members may benefit from joining the "program."
- Use encouragement and positive reinforcement. Scare tactics are NOT recommended.
- Follow up frequently. During each visit, measure linear growth and plot BMI.
- Referrals to outside resources such as nutritionists, psychotherapists, and exercise trainers may be useful.
One general nutritional and lifestyle approach is the 5-4-3-2-1-Go! program:
Servings of fruit and vegetables daily
Servings of water daily
Servings of low fat dairy daily
Hours or less of screen time daily
Hour or more of physical activity daily
These simple approaches will help the patient to make concrete changes that will help them to obtain and maintain a healthy weight.
CPS has several ongoing programs designed to fight obesity and promote healthy lifestyles. The schools offer breakfasts and lunches meant to be nutritious with a goal of teaching students the basics of healthy eating. Additionally, students may qualify for free or reduced (40¢ per meal) lunches; breakfast is free for all students. There is an application process, and not all parents are aware of this program. The school district has also established a snack vending approved product list to ensure an appropriate nutritional environment.
The Nutritional Support Services at CPS has lead to the elimination of all but skim milk in the school, eliminated fryers, and has increased student exposure to healthy eating by increasing enrollment in the various meal options available to CPS students.
For more information about local Chicago efforts to fight obesity, click on the link below:
- Hales CM, Carroll MD, Fryar CD, Ogden CL. Prevalence of obesity among adults and youth: United States, 2015–2016. NCHS data brief, no 288. Hyattsville, MD: National Center for Health Statistics. 2017.
- Kipping, Ruth R., Russell Jago, Debbie A. Lawlor. “Obesity in children. Part 1: Epidemiology, measurement, risk factors, and screening.” British Medical Journal. 2008; 337:a1824.
- Klish, WJ and Skelton, JA. Definition, epidemiology, and etiology of obesity in children and adolescents. AG Hoppin (Ed.), UpToDate. Updated February 12, 2020. https://www.uptodate.com
- Nader, Philip R., Marion O'Brien, Renate Houts, Robert Bradley, Jay Belsky, Robert Crosnoe, Sarah Friedman, Zuguo Mei, Elizabeth J. Susman. “Identifying Risk for Obesity in Early Childhood.” Pediatrics. 2006; 118(3):e594-e601.
- Skinner AC, Ravanbakht SN, Skelton JA, Perrin EM, Armstrong SC. Prevalence of Obesity and Severe Obesity in US Children, 1999–2016. Pediatrics. 2018;141(3):e20173459.
- Whitlock, Evelyn P., Selvi B. Williams, Rachel Gold, Paula R. Smith, Scott A. Shipman. “Screening and Interventions for Childhood Overweight: A Summary of Evidence for the US Preventive Services Task Force.” Pediatrics. 2005; 116(1):e125-e144.