Obesity in children has increased in recent decades. Behavioural and environmental factors are primarily responsible, although genes play an important role in regulation of body weight.
Calculating body mass index (BMI) is the most widely accepted method of screening for obesity in children. Abnormal BMI cut-offs in children are determined by age- and sex-specific percentiles.
Impaired glucose tolerance and type 2 diabetes mellitus are prevalent in children with obesity.
Preventing excessive weight gain in children is of paramount importance in confronting the obesity epidemic, as obesity is difficult to treat at all ages, and obese children tend to become obese adults.
The mainstay of treatment is lifestyle modification to improve diet and increase physical activity. Pharmacotherapy and bariatric surgery may be considered as an adjunct to lifestyle modification in severely obese adolescents.
Obesity is a condition of excessive body fat or adiposity that exceeds healthy limits.
The most widely accepted method to screen for excess adiposity is calculation of body mass index (BMI). Abnormal BMI cut-offs in children are determined by age- and sex-specific percentiles based on growth charts, as the amount of body fat changes with age and differs between boys and girls.
A BMI between the 85th and 94th percentiles is defined as overweight, and a BMI ≥95th percentile (or ≥ to 30 kg/m2, which ever is lower) is defined as obesity. Severe obesity is defined as BMI of 120% of the 95th percentile. For children aged <2 years, BMI normative values are not available. Weight-for-height values above the 95th percentile in this age group can be categorised as overweight.
The World Health Organization 2006 growth standard is recommended in many countries for children aged 0–5 years, and for children aged 0–2 years in the US. WHO: Child growth standards. Opens in new window
History and exam
Key diagnostic factors
- body mass index (BMI) ≥95th percentile
- weight ≥95th percentile for height
Other diagnostic factors
- increased waist-hip ratio
- obese parents
- rapid weight gain in infancy
- weight gain in early childhood
- non-Hispanic black or Hispanic ethnicity
- poor socioeconomic status
- sedentary lifestyle
- intrauterine growth restriction
- maternal gestational diabetes
- diet high in energy-dense foods, fast foods, and high-sugar beverages
- screen time >2-3 hours/day
- sleep deprivation
- exposure to corticosteroids, antibiotics, or acid-suppressing medication
- urban environment
- maternal smoking in pregnancy
Investigations to consider
- fasting blood glucose
- serum lipids
- liver function tests
- bioelectric impedance analysis
- abdominal CT or MRI
body mass index (BMI) ≥85th to 94th percentile (overweight)
BMI ≥95th percentile and <120% of 95th percentile (class 1 obesity)
BMI ≥120% of 95th percentile (class 2 and class 3 obesity)
- Primary hypothyroidism
- Secondary hypothyroidism
- Cushing syndrome
- Obesity: identification, assessment and management
- Guidelines on physical activity and sedentary behaviour
Weight problems in children
Weight problems in children: changing unhealthy habitsMore Patient leaflets
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