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JarmoJääskeläinen

Overweight and Obesity in Children

Essentials

  • Early prevention and management of childhood obesity is important since obesity in childhood is predictive of obesity in adulthood and has adverse health outcomes in both childhood and adulthood.
  • The treatment is family-centred and aimed at achieving lifestyle changes through establishment of inner motivation.
  • Diseases that cause obesity are rare, but they should be identified.

Definition of overweight and obesity

  • Obesity refers to the presence of excess adipose tissue. It is not known what amount of adipose tissue is detrimental to a child's health, and the classification is based on convention.
    • The weight of a child less than 2 years of age should be assessed in relation to the child's height (weight-for-height; the child's weight is compared with the median weight of children of the same gender and with the same height).
    • Overweight and obesity in children aged between 2 and 18 years can be assessed using both weight-for-height and the body mass index (BMI, kg/m²).
    • See Table T1.
  • BMI is useful in the assessment of weight from the age of 2 years. The body composition of a child and the normal BMI change with age. In children, the BMI correlates well with the amount of body fat. The criteria used to define overweight and obesity in children use age and gender matched BMI percentile cut-off points derived from the adult (18 years of age) cut-off points for overweight (BMI 25-30 kg/m²) and obesity (BMI > 30 kg/m²).
  • During a consultation, it is useful to express the child's BMI as a value corresponding to adult BMI (ISO-BMI). An ISO-BMI calculator will convert a child's BMI to the corresponding ISO-BMI Body Mass Index (Iso-Bmi) Calculator for Children.

Cut-off points for childhood overweight and obesity

Age (years)OverweightObesity
Weight-for-height (%)
<710-20>20
≥ 720-40>40
ISO-BMI
≥ 2-1825-30>30
  • Waist circumference correlates well with the child's body mass index and weight-for-height and should primarily be measured if there appears to be a discrepancy between weight and body structure. In the absence of reference values for the local population, a waist circumference that is more than half of the child's height suggests excess fat.

Incidence

Causes

  • Based on twin studies, the predisposition to become obese is highly genetic but the fact that obesity is becoming more common on the population level is due to an environment promoting obesity and to changed lifestyles.

Risk factors for childhood obesity

  • Parental obesity
  • Parents' health behaviour and the family's lifestyle
    • Maternal smoking during pregnancy
    • Insufficient exercise
      • Children whose parents lead a sedentary life are more likely to take less exercise.
    • Excessive consumption of sugary drinks
    • Frequent consumption of fast foods
    • Energy-dense snacks and snacking
    • Lengthy periods of uninterrupted inactivity, several hours of screen time
    • Insufficient amount of sleep at night
  • Family's low socioeconomic status (poor level of education, low income)
  • Size at birth
    • High birth weight as well as low birth weight in relation to gestational age and a rapid catch-up weight gain thereafter
  • Nutrition in infancy
    • High protein intake

Disease as a cause of obesity

  • Disease or its treatment is a rare cause of obesity in a child (1-2%).
  • An endocrine disease is possible in a child with abnormal linear growth.
    • Weight gain is normally accompanied by acceleration of linear growth, which usually continues for a few years.
    • As obesity will not increase the adult height, growth towards the end of puberty will be less than in normal-weight children.
    • Hypothyroidism is suggested by growth deceleration in association with weight gain. Obesity is often associated with slightly increased TSH levels (< 7 mU/l). If the T4V level is normal, a thyroid disease is improbable.
    • An endogenous Cushing's syndrome is extremely rare in children. It also causes growth deceleration with simultaneous weight gain. The face starts getting rounder and red and fat accumulates in the clavicular fossae, the neck and the waist. Persistence of this constellation (decelerated growth with weight gain) alone, even if thyroid tests are normal, gives reason to suspect the disease, which should be diagnosed in specialized care.
  • Short stature caught in growth screening or abnormal features suggest a possibility of a syndrome. Most syndromes causing obesity involve developmental delay.
  • Weight gain beginning before the age of 2 years, becoming severe by the age of 5 years and involving a tendency to binge eating suggests a single gene (monogenic) defect as the cause.
  • Childhood or adolescent obesity may be associated with a binge eating disorder Eating Disorders Among Children and Adolescents, which is probably underdiagnosed.
  • Many psychopharmaceuticals, some antiepileptic drugs (e.g. valproate), and glucocorticoids may cause weight gain. Adverse drug reactions should be assessed by the doctor in charge of the pharmacological treatment.

Consequences

  • Obesity has an effect on the child's physical, mental and social well-being.
  • Obesity persisting into adulthood
    • Fifteen per cent of normal weight school-age children, 36% of overweight children and 82% of obese children will be obese in adulthood.
  • The development of changes which predispose the individual to the emergence of obesity-associated diseases begins in childhood already.
  • Childhood obesity influences health and life expectancy in adulthood by increasing the risk of metabolic syndrome and the resultant risk of arterial disease complications, but achieving normal weight before adulthood will eliminate the increased risk.

Assessment

  • The growth and development of the child
    • Psychomotor development: age-appropriate or delayed development?
    • Assessment of size at birth (use data appropriate for local population)
    • Growth assessment (cf. the article Normal and Abnormal Growth in Childhood)
    • Assessment of pubertal development (see also Pubertal Development and its Disturbances)
      • Overweight and obesity increase the risk of premature adrenarche in girls and in boys.
      • Obesity advances pubertal development in girls.
      • Pubertal girls may have acne, hirsutism and irregular or missing periods but even in girls of normal weight, the menstrual cycle may not become normal until as many as 5 years after menarche.
      • In boys, overweight may speed up pubertal development but severe obesity may delay it.
      • In boys, obesity may be associated with gynaecomastia.
    • Timing of weight gain
      • Obesity beginning before the age of 2 years and becoming severe by the age of 5 may suggest an obesity syndrome or monogenic obesity.
      • In childhood obesity that becomes severe, weight gain usually starts before the age of 5 years.
  • Immediate family history (immediate family members, grandparents)
    • Obesity (childhood, adulthood), weight reduction surgery
    • Type 2 diabetes, maternal gestational diabetes
    • Disturbances in lipid metabolism
    • Coronary heart disease, hypertension and stroke (men < 55 years, women < 65 years)
  • Are there any symptoms suggestive of a disease?
    • See ”Disease as a cause of obesity” (above).
    • Pseudotumor cerebri Headache in Children: severe headache, papilloedema on examination (emergency referral)
    • Sleep disorders Sleep Disorders in Children and Adolescents: snoring on a regular basis, sleep apnoea episodes (polysomnography)
    • Polycystic ovary syndrome Polycystic Ovary Syndrome (PCOS): irregular menstruation (see above), acne and hirsutism (referral to an adolescent gynaecologist)
    • Slipped capital femoral epiphysis Hip Pain in Children: limp, pain in the hip or lower limb (x-rays, referral to a paediatric surgeon)
    • Depression Childhood Depression, anxiety (screening questionnaire, referral to a child/adolescent psychiatrist)
  • Lifestyle
    • A change in life situation predisposing to weight gain, for example a change in the family situation or childcare facility, going to school by car
    • Nutrition and meals
      • Meal schedule, number of snacks. Does the family eat together?
      • How often and how much?
      • Consumption of sugary drinks: fruit juices, squashes, soft drinks, energy drinks
      • Sweet and savoury treats
    • Exercise
      • Daily physical activity: from school to home, to a friend's house, to a leisure activity venue, household chores
      • Exercise outdoors during the week and over the weekend, outdoor activities with the family
      • Supervised exercise
    • Inactivity during the week and over the weekend
    • Duration of overnight sleep
    • Mental wellbeing
      • Mood, friends, bullying

Clinical status

  • Abnormal personal appearance, development
  • Check weight and height (in underwear).
  • Measure waist circumference at the midpoint between the lowest rib and the iliac crest, as necessary.
  • Blood pressure; ask the patient to sit down and relax, proper cuff size (at least 40% of the length of the upper arm), repeat measurement
  • Stage of puberty (picture 1)
    • Palpate breast tissue. The size of the penis can be checked by pushing away the surrounding fat tissue.
  • Palpation of the thyroid gland
  • Palpation of the abdomen: note the size of the liver.
  • Skin: acanthosis nigricans (dark brown pigmentation on the neck, axillae; pictures 2 3), striae, hirsutism, acne
  • Malposition of lower limbs when standing, a limp when walking
  • If there is headache, check the ocular fundi (papilloedema)

Investigations and interpretation

  • Diagnostic investigations: see “Disease as a cause of obesity” here
  • Test free T4 and TSH as a part of the diagnostic workup in overweight children with simultaneously decelerating linear growth not due to end of the period of growth in puberty, and once in all obese children.
  • Perform the blood tests listed in Table T3 once in obese children and perhaps again in puberty if the tests were last taken below the age of 10 years. However, an oral glucose tolerance test should be performed according to the local protocols or as described below. Even though changes in blood count are not common in obese children, basic blood count should be taken mostly to detect any significant iron deficiency.
  • Associated diseases and investigations T3
    • Disturbances in lipid metabolism
      • Cholesterol (Total, LDL, HDL), triglyserides
      • Obesity is often associated with a low plasma concentration of HDL cholesterol and an increased concentration of triglycerides.
      • Total cholesterol and LDL cholesterol levels are usually only mildly increased.
    • Disturbances in glucose metabolism
      • Fasting plasma glucose and HbA1c
      • Following local protocols, an oral glucose tolerance test is indicated in children over 10 years of age in the following circumstances:
        • prediabetes: fasting plasma glucose ≥ 5.6 mmol/l or HbA1c ≥ 39 mmol/mol
        • acanthosis nigricans skin lesion
        • an obese child whose 1st or 2nd degree relative has type 2 diabetes, or the child's mother has gestational diabetes
        • severe obesity (ISO-BMI > 35)
        • ALT > 80 U/l
    • Fatty liver
      • Increased ALT (girls > 22, boys > 25 U/l) is suggestive of fatty liver.
      • Significant suspicion of fatty liver if plasma ALT is clearly increased (> 80 IU/l) on repeat testing.
    • Blood pressure
      • Blood pressure requires closer assessment (checked weekly 3 times either at home or by a public health nurse) in the following cases:
        • In a child below school age if the systolic blood pressure is ≥ 110 mmHg or diastolic pressure ≥ 70 mmHg.
        • In a child of primary school age (< 13 years) if the systolic blood pressure is ≥ 115 mmHg or diastolic pressure ≥ 75 mmHg.
        • In a child ≥ 13 years of age if the systolic blood pressure is ≥ 120 mmHg or diastolic pressure ≥ 80 mmHg.
          • If blood pressure is elevated on repeat measurement, provide dietary and exercise instructions.
          • For the criteria for referral to specialized care in the case of severe hypertension, see below.

Interpretation of laboratory tests. Criteria for referral to specialized care, see below.

TestInterpretation*
Target levelPrediabetesDiabetes
Fasting plasma glucose
(mmol/l)		<5.65.6-6.9≥7.0
HbA1c
(mmol/mol)		<3939-47≥48**
2-hour plasma glucose
(mmol/l)		<7.87.8-11.0≥11.1
Target levelMild dyslipidaemiaEvident dyslipidaemia
Plasma total cholesterol
(mmol/l)		<4.54.5-5.2≥5.3
Plasma LDL cholesterol
(mmol/l)		<2.92.9-3.3≥3.4
Plasma HDL cholesterol
(mmol/l)		>1.11.1-1.0≤0.9
Fasting plasma triglycerides
(mmol/l)		< 10 yrs<0.850.85-1.1≥1.2
≥ 10 yrs<1.11.1-1.5≥1.6
Target levelMild fatty liverFatty liver or steatohepatitis
Plasma ALT
(U/l)		Girls<2323-79≥80
Boys<2626-79≥80
* Please note that the laboratory test reference values given in the article may differ from the reference values applied by individual laboratories. Check also values applied locally.
** Only indicative, not official diagnostic criterion

Treatment Prevention of Obesity in Children, Dieting as a Risk Factor for Eating Disorders in Children and Adolescents

  • Treatment goals
    • Early recognition of and intervention in weight gain
      • Treatment of obesity is more effective in children below 10 years of age than in older children.
      • An infant should not be defined as overweight or obese in front of the parents but the topic of nutrition can be broached.
      • The weight of primary school age or younger children should be broached with the parents, not the child.
      • The growth curve should be utilized when bringing the subject up as it also allows natural discussion of the timing of weight gain.
      • If the adolescent is of secondary school age or older, the discussion should be opened by asking what he/she thinks about him-/herself or his/her body. Do not call the adolescent overweight or obese but you can discuss weight and its interpretation naturally.
    • Lifestyle counselling for the whole family
    • Stopping weight gain (in overweight children) and reducing obesity (in obese children)
  • The simplest intervention is broaching the subject during a consultation.
    • You can ask an adolescent about his/her motivation for treatment and simultaneously work on it by using a motivational questionnaire. Find out about the availability of such questionnaires in your local language. Separate questionnaires/assessment scales may be available for adolescents and the parents of smaller children.
    • It is important to listen to both the child and his/her family . The conversation is rendered easier by open questions ("How do you feel about your child's growth/weight?” “What benefits or drawbacks would lifestyle changes bring?”).
    • Avoid a blaming tone of speech and remember that lifestyle instructions that seem easy to you are not usually easy for an obese child's family.
    • Body weight is not a measure of anybody's value as a human being; therefore, it is important to recognize the child's strengths together with the parents.
  • If the family is not motivated for treatment, motivation should be improved by means of motivational interview The Role of Motivational Interviewing in Changing Lifestyles and in Treatment http://equip-elearning.woncaeurope.org/.
  • If the current life situation ties up all the resources of the family, there is no point in attempting treatment but it is better to support the family in other ways and revisit the issue once the resources are better.
  • Prevention of obesity-associated diseases
    • Prevention of cardiovascular diseases involves other significant factors in addition to weight management: physical exercise, healthy food choices and non-smoking (including passive smoking), as well as measurable factors including normal blood pressure, ALT, cholesterol and fasting blood glucose levels.
    • Instead of talking about just weight it is better to guide the patient/family to self-assessment of lifestyle and to setting appropriate goals. The more the health factors are on target already in childhood, the more favourable the arteriovascular health will be in the future.

Modification of lifestyle

  • Acknowledge advantageous health-promoting lifestyle habits by giving positive feedback.
    • Empowerment improves self-esteem and helps to discover capabilities.
  • It takes practice to learn a new habit.
    • A change is easier to implement if there are interim goals that are agreed together, recorded and monitored at a follow-up visit.
  • The child should be accepted as him-/herself and the family should be supported in achieving a change: "You decide, you are capable and you are worthy."
    • While counselling, bear in mind that the family has freedom of choice without forgetting the responsibility of the parents for their child.

Practical interventions to modify lifestyle

  • Guide (yourself / public health nurse / therapeutic dietitian) the child and his/her family towards healthier eating habits (see locally available dietary recommendations for families with children).
    • Regular meal schedule which reduces the need for energy dense snacks
    • A generous daily intake of vegetables, fruit and berries (one fist-sized portion 3 to 4 times daily for small children, 5 to 6 times daily for bigger children)
    • Moderation in sugar intake (sugary drinks, sweets etc.)
    • Minimising the consumption of energy dense, fatty foods
    • The adult is responsible for what is eaten, when and where. The child is responsible for how much is eaten.
  • Activate the child and the family to daily physical exercise.
    • Physical/outdoor activity for children below 8 years of age at least 3 hours/day, for school-age children > 1.5 hour/day (half of this at a brisk pace)
    • It is advisable that during exercise the child now and then becomes slightly breathless and the heart rate increases.
  • Encourage the family to reduce sedentary time to less than 2 hours/day. In addition, it is advisable to interrupt such inactivity at least every half an hour.
  • Instruct the parents to take care that the child gets sufficient sleep during the night.
    • Sleep during the night: > 11 hours at the age of 0 to 5 years, > 10 hours at the age of 5 to 10 years, > 9 hours at the age of over 10 years

Reversing weight gain in a child

  • If the current weight (kg) is maintained or moderately increased, a child growing in height will start to slim down.
  • The treatment goal in severe obesity (ISO-BMI > 35), and in obesity-associated diseases, is permanent weight loss (achieved by losing 0.5-1 kg/month).

Professional co-operation

  • The management of childhood obesity is usually carried out by primary health care professionals.
  • The division of work should be decided on at a regional level, the ultimate goal being a structured care network where everyone knows their role. Contradictory instructions should be avoided, in particular: the goals and the instructions must be consistent.
  • A regionally agreed obesity treatment programme will make the work clearer and reduce unplanned visits.
  • Local variation exists as regards the intensity and duration of interventions, the availability of one-to-one or group counselling, and the possibility of mini-interventions with specialist health professionals (dietitian, physiotherapist, psychologist), but effective treatment should be ongoing and sufficiently long, at least one year.
  • Mini-interventions with specialist health workers are recommended. The aim is to improve the effectiveness of the lifestyle counselling.

Monitoring obesity-associated diseases

  • If the screening tests for associated diseases yield abnormal results (disturbed glucose metabolism, dyslipidaemia, abnormal liver function tests or elevated blood pressure), give the patient advice about lifestyle modification, arrange dietary counselling and refer to specialized care, as necessary.
    • Prediabetes: depending on local protocols, either refer for specialized care (non-urgent referral) or provide lifestyle counselling and arrange dietary counselling. If prediabetes was diagnosed based on fasting blood glucose or HbA1c, perform a glucose tolerance test. Check the glucose metabolism again after 1 year.
    • Diabetes: refer to specialized care (appointment there within 1-7 days). Remember that in children type 1 diabetes is more common than type 2 diabetes: therefore verify that diabetes is asymptomatic. A child with symptoms must be referred without delay to specialized care as an emergency case.
    • An elevated blood pressure may be monitored for one month, followed by a check-up visit and repeat testing at every visit. The criteria for referral to specialized care are given below.
    • In the case of dyslipidaemia or slightly elevated ALT levels, give lifestyle counselling and arrange dietary counselling. The criteria for referral to specialized care are given below. Check abnormal lipid levels or ALT after 6 months.
    • If the screening tests in an obese child below 10 years of age yield normal results but the obesity persists, schedule follow-up tests at the age of 14-16.
    • Follow-up of blood pressure should be included at every health visit.

Referral to a paediatrician

  • Severe obesity (ISO-BMI > 35) if this has been locally agreed
  • Diagnosed hypothyroidism or suspicion of other disease as the cause for obesity
  • Weight reduction surgery may be considered from late puberty on for morbidly obese (ISO-BMI > 40) adolescents or severely obese (ISO-BMI > 35) adolescents, the latter with an associated disease.
  • Obesity-associated disease
    • Diabetes (always)
    • Prediabetes, if this has been locally agreed
    • Manifest hypertension: 1-6 years 115/75 mmHg; 6-10 years 125/85 mmHg; 11-18 years 140/90 mmHg or stage 2 hypertension (see calculator http://www.bcm.edu/bodycomplab/BPappZjs/BPvAgeAPPz.html)
    • Severe dyslipidaemia: plasma total cholesterol > 6 mmol/l, plasma LDL cholesterol > 4 mmol/l or fasting plasma triglycerides > 3 mmol/l after dietary counselling
    • Severe fatty liver, ALT > 80 U/l
    • Suspected sleep apnoea (referral for sleep polygraphy)
    • Epiphysiolysis (referral to a paediatric surgeon)
    • Suspected PCOS (severe hirsutism, acne or absent/irregular menstruation; gynaecologist or paediatric endocrinologist)
      • Menstruation may normally be irregular for as long as 5 years after menarche.
    • Binge eating, depression or anxiety (according to local protocols)

References

  • Armstrong S, Lazorick S, Hampl S et al. Physical Examination Findings Among Children and Adolescents With Obesity: An Evidence-Based Review. Pediatrics 2016;137(2):e20151766. [PubMed]
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  • Bjerregaard LG, Jensen BW, Ängquist L et al. Change in Overweight from Childhood to Early Adulthood and Risk of Type 2 Diabetes. N Engl J Med 2018;378(14):1302-1312. [PubMed]
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  • Dalla Valle M, Laatikainen T, Lehikoinen M et al. Paediatric obesity treatment had better outcomes when children were younger, well motivated and did not have acanthosis nigricans. Acta Paediatr 2017;106(11):1842-1850. [PubMed]
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  • Skinner AC, Perrin EM, Moss LA et al. Cardiometabolic Risks and Severity of Obesity in Children and Young Adults. N Engl J Med 2015;373(14):1307-17. [PubMed]
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Evidence Summaries ⬆