History and exam

Key diagnostic factors

common

body mass index (BMI) ≥95th percentile

Most widely accepted measure of body fat (weight in kilograms divided by height in meters squared).[64]

Accurate and replicable measurements of both height and weight are important to calculate BMI.

Abnormal BMI cutoffs in children are determined by age- and sex-specific percentiles based on the Centers for Disease Control and Prevention growth charts. CDC: growth charts Opens in new window

A BMI between the 85th and 94th percentile is defined as overweight.​[4][64]​​​ Obesity is classified as: class 1 (BMI ≥95th percentile); class 2 (BMI 120% to 139% of the 95th percentile, or an absolute BMI of ≥35 kg/m² to <40 kg/m², whichever is the lower for age and sex); class 3 (BMI ≥140% of the 95th percentile or an absolute BMI ≥40 kg/m², whichever is the lower for age and sex).[3][5][6][65]​​​

weight ≥95th percentile for height

For children ages <2 years, BMI normative values are not available. Weight-for-height values above the 95th percentile in this age group can be categorized as overweight.[7]

Other diagnostic factors

common

increased waist-hip ratio

Can be used as an indirect measure of visceral adiposity (which has been shown to be associated with cardiovascular and metabolic risk factors).[67][68]

Measuring waist circumference is noninvasive and may be helpful in addition to BMI to identify overweight children at a higher metabolic risk. Waist circumference percentiles have been developed for children ages 2 to 19 years.[2] However, the cutoff values that would indicate risk above that of BMI measurement are not available.[59]

hypertension

Children with overweight or obesity have a higher prevalence of hypertension; thus, blood pressure should be monitored closely. Approximately 13% of overweight children have elevated systolic blood pressure, and 9% have elevated diastolic blood pressure.[64]

Risk factors

strong

parents with obesity

A child's risk of obesity is increased with ≥1 parents with obesity.[39]​​

Maternal pre-pregnancy obesity and gestational weight gain are associated with fetal macrosomia and childhood obesity.[22][23] In addition, maternal obesity before pregnancy, mothers who gained more weight during pregnancy and gestational diabetes are all associated with increased birth weight.[40][41]

rapid weight gain in infancy

Rapid weight gain during infancy has been associated with an increased risk of childhood obesity.[14][15][16][42]​​

weight gain in early childhood

Children who have a body mass index (BMI) >85th percentile between the ages of 24 and 54 months have a 5-fold greater likelihood of being overweight at age 12 years.[17]

Children with obesity at age 8 years will tend to have more severe obesity, as well as increased morbidity, as adults.[18][19]

non-Hispanic black or Hispanic ethnicity

Epidemiologic studies have shown that Hispanic children and African-American children have a higher incidence of obesity, compared with white and Asian-American children.[5]

Associations between BMI, physical activity, and TV/video viewing vary according to sex and race.[21]

poor socioeconomic status

Children raised in poor families have a higher risk of obesity.​[12][13][25][42]​​

sedentary lifestyle

Children who get less exercise are at higher risk of obesity.​​[27][43]

weak

intrauterine growth restriction

Poor nutrition in utero has been correlated with obesity in childhood and adulthood.[25]

maternal gestational diabetes

Maternal gestational diabetes is associated with increased newborn fat mass, higher BMI, and higher prevalence of overweight/obesity in children.[24]

diet high in energy-dense foods, fast foods, and high-sugar beverages

Implicated as a risk factor for the development of obesity in children.[44] The impact of other factors such as specific eating patterns (eg, frequent snacking, skipping breakfast), portion sizes, eating speed, and glycemic load on obesity development is still not clear but may be a factor.[44] However, dietary choices alone do not consistently lead to obesity.

screen time >2-3 hours/day

Obesity risk is increased in children who have daily screen time (e.g., television, video games, internet) >2-3 hours per day.[28] Screen exposure influences risk of obesity in children and adolescents via increased exposure to food marketing, increased thoughtless eating while watching screens, displacement of time spent in physical activities, reinforcement of sedentary behaviors, and reduced sleep time.[45][46]

sleep deprivation

Epidemiologic studies show a link between short sleep time and development of obesity in infants, children, and adolescents.​[8][29]

exposure to corticosteroids, antibiotics, or acid-suppressing medication

Exposure to long-term corticosteroids increases the risk of obesity.[31]

Exposure to antibiotics or acid-suppressing medication at age <2 years has been associated with increased risk of obesity in later childhood.[32]

urban environment

One systematic study of many exposures in the urban environment suggests that an exposure pattern characterized by higher levels of ambient air pollution, road traffic and road traffic noise is associated with increased childhood obesity risk.[47]

maternal smoking in pregnancy

There is an association between maternal prenatal smoking and childhood overweight and obesity.[42]​[48]

maternal consumption of ultra-processed foods

Maternal consumption of ultra-processed food during the child rearing period was found to be associated with an increased risk of overweight or obesity in offspring.[49]

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