Obesity in Children

In the past, obesity has been seen as a problem of adults, becoming more prevalent with advancing age. Fat children have been recognised in literature with Charles Dickens' portrayal of the fat boy in The Pickwick Papers, and Billy Bunter in the 20th century. They were notable because fat children were uncommon.

Now obesity is no longer rare in children and the prevalence is increasing at an alarming rate. Pathological processes (see 'Complications' below) start early in life and are accelerated by obesity.

You may also find the following records relevant:

Obesity in Adults
Bariatric Surgery

• Globally, there are an estimated 22 million overweight or obese children.²
• The greatest annual increases in obesity of school-aged children since 1970 have occurred in North America and Western Europe. However, 75% of overweight and obese children live in low and middle income countries.²
• The most recent health survey in England (2007) has shown that there has been no significant increase in average weight of 2-15 year-olds since the last survey, unlike the survey before which showed a rise from 1995-2001.
• However, within this group, there was an overall increase in levels of obesity since 1995 (from 11% to 17% among boys and 12% to 16% among girls). This increase was due to a rise both in the younger (2-10) and older (11-15) age groups:³
  • An average of 9.6% of reception year children are obese (ages 4-5)
  • An average of 18.3% of year 6 children are obese (ages 10-11)
• Most recent trends suggest that the rising trend in obesity may be flattening out but data over the coming years will be needed to confirm whether this is a continuing pattern.²

Obesity is basically caused by an imbalance between energy input and expenditure.² There are numerous factors that are thought to contribute to this trend. A few will be considered here. It is worth noting that studies investigating the role of diet or activity are generally small and include diverse methods of risk factor measurement.

Dietary habits

There is a growing cohort of children who develop bad eating habits and a taste for junk food that is high in fat and fast carbohydrates. A clear causal link has yet to be established between fast food and obesity in children (it is present in adults).³

Exercise

Reduction of physical exercise in the absence of dietary modification contributes to weight gain. Compulsory sport is in decline although recent studies suggest that school-based activity programmes aimed to promote physical exercise actually have little impact on children's BMIs.³ Long periods in front of the television or playing on the games console also contribute to the increasingly sedentary lifestyle.²

Sleep

Sleep deprivation has been suggested as a contributory factor. A possible trend of children going to bed later may be in part responsible. Lack of physical exercise may also lead to poor sleep.⁴ Two hormones, leptin and ghrelin, may be important. Leptin is released by fat cells to tell the brain that fat stores are adequate and ghrelin is released by the stomach, as a signal of hunger. In people with too little sleep, leptin levels are low and ghrelin levels high.⁵ Both these would encourage an individual to eat more.

Genetic contribution

Parental obesity is one factor that does result in increased risk of childhood obesity.⁶ However, this does not mean that obesity is genetically inherited. Read a more full discussion in the article on Obesity in Adults.

Socio-economic situation

The relative contribution of lifestyle factors remains largely unknown. Although some have claimed no clear relationship is reported between socio-economic status (SES) in early life and childhood fatness, others have found a relationship.⁷ However, a strong consistent relationship is observed between low SES in early life and increased fatness in adulthood. Women who change social class (social mobility) show the prevalence of obesity of the class they join; this is not true of men.¹

Other risk factors⁶

• High birth weight²
• Timing or rate of maturation
• Other behavioural or psychological factors
• Physical conditions such as endocrine causes (rare):^8,9
  • Hypothyroidism - especially Down's syndrome.
  • Cushing's syndrome - look for truncal obesity, hypertension, hirsutism.
  • Growth hormone deficiency - there may be weight gain with delayed puberty.
  • Muscular dystrophy and other causes of immobility.
  • Polycystic ovary syndrome.
  • Hypothalamic damage.
  • Spina bifida.
  • Genetic syndromes associated with hypogonadism.

It can be a delicate issue to raise with a parent and this may mark the (good or bad) start to a long therapeutic period. The issue may be raised:

• If the family expresses concern about the child's weight. Try: "We can measure [child's] weight and see if he is overweight for his age."
• If the child has weight-related co-morbidities. Try: "[Condition] can sometimes be related to a child's weight. I think we should check [child's] weight."
• If the child is visibly overweight. Try "I see more children these days who are a little overweight. Could we check [child's] weight?"

This may be the first time that weight has been raised with the family. It is a time to be reassuring and supportive. "By taking action now, we have a chance to improve [child's] health in the future."

Any gold standard for diagnosing obesity would be based on body fat content. Adiposity can be directly measured (e.g. densitometry, scanning using dual energy X-ray absorptiometry) and indirectly (anthropomorphic measurements, bio-electrical impedance and air displacement plethysmography).² This is not practical in primary care. In adults body mass index (BMI) is often used (with certain caveats attached).

• As a rule of thumb, in children a BMI of 20 is significantly overweight and the younger the child, the more this is so.
• However, BMI per se is not generally a suitable way to assess obesity in children although it can be used provided that it is moderated by use of the UK90 charts¹⁰ or the like, to be used in children over 2 years old. In this case, a child with a BMI over the 91st BMI percentile is said to be overweight and a child over the 98th BMI percentile is considered obese. These precise figures do vary slightly from one publication to the next.
• In infants between 2 weeks and 24 months old, the 2006 World Health Organisation child growth standards for infants and children are used.²
• The value of waist circumference in children is unknown and so measuring it is not recommended.
• Overweight children tend to be tall but centile charts may show that a child is on the 75th centile for height and the 97th centile for weight. This much higher centile for weight than for height suggests obesity. If an overweight child is not tall, refer to a paediatrician.
• In the article Centile Charts and Assessing Growth, the problem of diagnosing childhood obesity is discussed more fully.

Parents can be remarkably obtuse in noting that a child is overweight³ and charts may be needed to drive the message home. "Puppy fat" is a common excuse or assertions that "his glands are the problem." Endocrine causes for childhood obesity are rare. It is worth stressing that obesity is a clinical term with health implications rather than just the way somebody looks.¹¹

1. Explore why help is being requested; is it the child or the family or are there comorbid problems? The child may have been flagged up during the course of the National Child Measurement Programme.^1,3
2. Perform physical examination, looking for features of physical causes (see 'Other risk factors' above).
3. If acceptable to the child, evaluate pubertal development.
4. Height and weight should be in light clothing with no shoes.
5. Test urine for protein and glucose. Ideally check blood pressure but the cuff needs to be suitably sized.
6. The National Institute for Health and Clinical Excellence (NICE) recommends tailored clinical intervention if a child's BMI (adjusted for age and sex) is at the 91st centile or above and that assessment for comorbidities should be considered if their BMI is at the 98th centile or above, using 1990 UK reference charts.¹¹

Overweight children and adolescents can be managed in primary care if there is a positive attitude to weight management.⁹

General points

• Rapid changes in BMI occur during normal growth; there is a great potential for reducing overweight in children and adolescents.⁹
• Unless the child is seriously overweight or has significant co-morbidities, be led by the child's/parent's wishes.¹
• As children are still growing, the aim is often not weight loss but weight maintenance or even a reduction in the rate of gain of weight.
• School, family and societal interventions should be considered in the management and prevention of obesity in children. This may include involving parents in weight loss programmes.¹¹
• The suggestion that inadequate sleep in children may aggravate obesity has been noted above. Ensuring adequate sleep may be important.
• Beware of potential underlying psychological factors. There may be "comfort eating" or even clinical depression that needs treatment.
• Overweight adults need caring, compassionate and empathetic attention. This is even more important in children. Praise success at every occasion, however small.¹¹

Diet and exercise

The primary aims of management are dietary modification and the initiation of exercise. Losing weight without exercise is very difficult but the obese child may find it very tough taking exercise up initially.

Diet

• NICE does not recommend using a dietary approach alone.¹¹
• It may be helpful to keep a food diary (assists cognitive approach). Do not forget snacks and drinks.
• It is very unpleasant being hungry and, rather than just cutting back on all food, it may be easier to move to a diet with less fat and more fibre in it.
• As with adults, herbal and "natural" wonders are also to be avoided as are diets promoted by "celebrities".
• There may be occasions where there is benefit in referral to a dietician, particularly where there is a large amount of weight to be lost and caloric cut has to be balanced by adequate nutrition for ongoing developmental needs.
• This is not easy for the patient and it is important to be positive and reinforcing.

Exercise

• The value of exercise is more than just the calories expended in the session. It tends to increase basal metabolic rate and, after vigorous exercise, metabolism is stimulated for the next 36 hours. It also helps people to feel good about themselves.
• Overweight children often shun exercise because of poor mobility, ready fatigue and "being no good at games". It is important to discuss the options to find something appropriate and sustainable. They may be less disadvantaged at swimming for example but the attire shows every bulge.
• The age and aptitudes of the individual must be taken into account. It must be something that the individual will enjoy or he will not persevere. This is very important, as the ethos of exercise is not just for the duration of weight loss but for life.
• NICE recommends a total of 60 minutes of at least moderate exercise each day (in one session, or more, shorter sessions lasting a minimum of 10 minutes).
• Exercise need not always be 'formal' - walking, using stairs, cycling and active play all count.
• It is very helpful to involve all the family in development of an active lifestyle.⁹

Drugs

The drug management of obesity has been more fully discussed in our record on Obesity in Adults (see link at top of this record).

• Drug treatment is not usually recommended for children. Neither orlistat nor sibutramine currently has market authorisation for use in children. Pharmacists will not issue over-the-counter orlistat to individuals under 18 years of age.¹²
• In exceptional cases, where there are physical comorbidities (such as orthopaedic problems or sleep apnoea) or severe psychological comorbidities, there may be a role for drug treatment after dietary, exercise and behavioural programmes have been started and evaluated.¹³
• NICE does not recommend the use of these drugs in children less than 12.
• Treatment should be initiated in a specialist paediatric setting, by multidisciplinary teams with experience of prescribing in this age group. It may be continued in primary care, if local circumstances and/or licensing allow.
• Regular monitoring of physical parameters, psychological, behaviour, diet and exercise should be part of the treatment package.
• Treatment regimes shouldn't exceed 6-12 months.¹³

It is worth noting that there are a number of drugs that aggravate weight gain¹⁴ and, if the patient takes them, it may be advisable to consider an alternative. Most of such drugs would not be prescribed for children.

• Antidepressants including tricyclics, mirtazapine, monoamine oxidase inhibitors.
• Anticonvulsants, particularly sodium valproate, gabapentin, vigabatrin.
• Antipsychotics, especially the atypical antipsychotics amisulpiride, aripiprazole, clozapine, olanzapine, quetiapine, risperidone, and zotepine.
• Corticosteroids.

Surgery¹¹

Bariatric surgery is limited to the severely obese who are refractory to other management. In young people, it is generally not recommended but may be considered in exceptional circumstances if:

• Physiological maturity has been reached, or almost reached.
• The BMI is >40 or if it is between 35 and 40 with significant comorbidities.
• All appropriate non-surgical measures have failed to produce adequate results over 6 months.
• They are receiving intensive specialist assessment.
• They are fit for anaesthesia and surgery.

Bariatric surgery is associated with larger decreases in BMI and greater improvements of some metabolic markers but it is associated with considerable risks¹³ (go to link provided in introduction for more information on bariatric surgery).

Cognitive approach

This is important and should accompany all the other approaches described above. It is as important in helping the individual understand the problem as it is to help them through treatment. Cognitive approaches seem to work best in pre-pubertal children.¹⁵ See record Cognitive and Behavioural Therapies which discusses behaviour modification.

Follow-up

As with any chronic disease, follow-up must be arranged. This implies interest in the patient's progress. A fortnight to a month would be appropriate at first, with intervals getting longer with time; however, treat it as a chronic disease. The practice may have a nurse-run weight control clinic.

The achievement of a target weight is not the end of the process. Obesity is a chronic disease and needs to be managed throughout the person's life, as relapse is common. "Yo-yo dieting" with weight going up and down is undesirable and unhealthy.

Before referral to secondary care, consider referral to community-based treatment programmes such as MEND (mind, exercise, nutrition . . . do it!) - the only programme provided nationwide in the United Kingdom.¹³ It is a twice-weekly, 10-week course for groups of children aged 7-13 and their parents. The course covers physical activity, behaviour change and nutrition. To be included, children must be on or above the 91st to the 98th BMI centile (criteria vary locally). Consider referral to a paediatrician if:⁹

• There is serious morbidity related to the weight.
• The height is below the 9th centile, the child is unexpectedly short for the family or if there is a slowed growth velocity.
• There is precocious or delayed puberty (i.e. younger than 8 or older than 13 in girls and 15 in boys).
• There is a significant learning disability.
• There are symptoms/signs suggestive of an endocrine or genetic problem.
• There is severe or progressive obesity before the age of 2.
• You have other significant concerns.

These include:¹

• Insulin resistance and type 2 diabetes - maturity onset diabetes of the young (MODY)
• Breathing problems, e.g. sleep apnoea and asthma
• Orthopaedic conditions
• Raised liver enzymes - indicative of non-alcoholic fatty liver disease²
• Psychosocial morbidity³
• Increased likelihood of obesity in adulthood

There are then problems if these children carry their obesity into adulthood.³ There may be an increased future risk of impaired fertility, some cancers, early cardiovascular disease, dyslipidaemia and hypertension.

It is often assumed that fat children will evolve into fat adults and they have little chance of overcoming their obesity, whilst the risk factors associated with obesity will be accentuated by having started so early in life. This assumption may not be supported by the evidence. The Thousand Families Study traced a cohort who were born in 1947. The study from Newcastle¹⁶ traced 932 people, of whom 412 were examined at age 50. The study concluded that when using a measure of fatness that was independent of build, there was little association between obesity in childhood and adulthood. Only children who were obese at 13 showed an increased risk of obesity as adults. No excess adult health risk from childhood or teenage overweight was found. Being thin in childhood offered no protection against adult fatness and the thinnest children tended to have the highest adult risk at every level of adult obesity.

Another study took a cohort born in 1970 to assess the effect of childhood obesity on adult socio-economic, educational, social, and psychological outcomes.¹⁷ Of the 8,490 participants with data on body mass index at 10 and 30 years, 4.3% were obese at 10 years and 16.3% at 30 years.

Of that same group, 8.2% were obese at 16 and 16.4% were obese at 30. Of those who were obese at 16, just over 60% were also obese at 30.¹⁸ Hence, obesity in youth must be seen as a strong risk for adult obesity but more than a third of those who were obese at 16 had conquered it at 30.

These studies serve as important reminders that not all cases are hopeless and that, if childhood obesity is overcome, individuals can hope for a much brighter outlook in their adult lives. Obesity limited to childhood has little impact on adult outcomes. Persistent obesity in women is associated with poorer employment and relationship outcomes. Efforts to reduce the socio-economic and psychosocial burden of obesity in adult life should focus on prevention of the persistence of obesity from childhood into adulthood.

Currently, the UK National Screening Committee's policy is that there is not enough evidence available to recommend screening children for obesity, as few obesity prevention interventions have been shown to be effective in children.¹³ However, longitudinal observational studies in children have suggested that opportunistic monitoring of growth charts after 2 years of age may be beneficial. In 2005, an annual National Child Measurement Programme was introduced in England for surveillance (not screening) of two school year groups: reception and year 6. From 2008/9, new legislation will allow these statistics to be used by government organisations to tackle obesity.

The English cross-government "Healthy Weight, Healthy Lives" strategy aims to reverse the trend in rising childhood obesity so that levels return to those of 2000 by 2020. This strategy has several facets:

• The healthy growth and development of children, e.g. early identification of at-risk children, breastfeeding promotion, cookery classes.
• Promoting healthier food choices, e.g. Ofcom review of restrictions on the advertising of unhealthy foods.
• Building physical activity into people's lives, e.g. the "Walking into Health" campaign, development of "healthy towns".
• Creating incentives for better health at work and financially.
• Personalised advice and support through NHS Choices.

NICE has developed guidelines aimed at organisations (e.g. PCTs), health professionals and the general public regarding steps to prevent obesity.