Obesity in Adolescents

Many environmental factors are associated with obesity in adolescents, including various social determinants of health, ubiquity of foods with a high glycemic index, lack of access to healthy foods, sedentary habits associated with the use of digital and electronic media, and sleep disorders. Genetic factors appear to play a major role, and specific genetic polymorphisms are being investigated.

Endocrine disorders are a rare cause of obesity, and potential underlying diseases include hypothyroidism, pseudohypoparathyroidism, cortisol excess, and growth hormone deficiency. Adolescents with weight gain caused by endocrine disorders usually have other signs of the underlying disorder.

• History and physical examination

• Body mass index (BMI)

• Evaluation for comorbidities or endocrine disorders, if indicated

Clinical definitions include (percentiles are in comparison to children and adolescents of the same age and sex) the following (1):

• Overweight: BMI ≥ 85th to < 95th percentile

• Obesity: BMI ≥ 95th percentile

• Class 2 obesity: ≥ 120% to < 140% of the 95th percentile or BMI ≥ 35 kg/m² to < 40 kg/m² (whichever is lower based on age and sex)

• Class 3 obesity: ≥ 140% of the 95th percentile or BMI ≥ 40 kg/m² (whichever is lower based on age and sex)

BMI is commonly used as a measure in clinical care; however, this number may be misleading because it does not take into account muscle mass, bone density, overall body composition, and racial and sex differences.

Primary endocrine (eg, cortisol excess, hypothyroidism) or metabolic causes are uncommon but should be ruled out if height growth slows significantly. If the child has short stature and hypertension, Cushing syndrome should be considered.

If comorbidities (eg, diabetes, hypertension, dyslipidemia, obstructive sleep apnea, mental health disorders) are diagnosed or suspected, laboratory evaluation, additional testing, or referrals to specialists are done.

• Behavior and lifestyle interventions

• For adolescents ≥ 12 years with BMI ≥ 95th percentile, weight-loss medications may be considered

• For adolescents ≥ 13 years with BMI ≥ 120% of 95th percentile, evaluation for metabolic and bariatric surgery

All children and adolescents with obesity should be given intensive health and lifestyle change strategies that address nutrition, physical activity, and health behavior.

Adolescents ≥ 12 years with obesity (BMI ≥ the 95th percentile for age and sex) may be offered medications for weight loss (1).

Adolescents ≥ 13 years old with class 2 or class 3 obesity (BMI ≥ 120% or ≥ 140% of the 95th percentile for age and sex) may be referred for evaluation for metabolic and bariatric surgery (1).