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OBESITY AND METABOLIC COMPLICATIONS
Childhood obesityLaura Stewart
Management programmes should use behavioural change tools
C A change in BMI SDS of �0.25 to �0.5 may reduce clinical risk
factors in obese children
C In severe obesity adolescents with co-morbidities, the use of
the anti-obesity drug, orlistat, could be considered under
supervision from specialists
C In extreme obesity, for adolescents with severe co-morbidities,
bariatric surgery could be considered
AbstractObesity is now a common childhood disease and is widely acknowledged
as having become a global epidemic. There are well-recognized health
consequences of childhood obesity, both during childhood and adult-
hood, affecting health and psychological welfare. Clinicians working
with obese children should have knowledge of the components of
a healthy lifestyle and understand the importance of interacting with
the child and family in a positive, empathetic and non-judgemental
manner. Most parents will be unaware of the impact of obesity in child-
hood and adolescence and many parents may even be unaware that
their own child is obese. UK Body Mass Index (BMI) centile charts with
the recommended cut-off points should be used to diagnose childhood
obesity. Evidence-based clinical guidelines conclude that treatment pro-
grammes should be multi-component, targeting changes in diet, physical
activity and sedentary behaviour (screen time). The use of behavioural
change strategies is consistently recommended in evidence-based guid-
ance on management. Guidelines suggest that in the case of severe to
extreme obesity in adolescents with co-morbidities, anti-obesity drugs
and bariatric surgery may be considered as part of a treatment plan.
Keywords adolescents; body mass index; body weight; childhood;
obesity; treatment
Childhood obesity is widely acknowledged as having become
a global epidemic.1,2 The prevalence of childhood obesity in the
UK dramatically increased over a short period of time in the early
1990s.3,4 The importance of childhood obesity has gained
national significance with the publication of expert reports5 and
evidence-based guidelines.6,7 Doctors in primary, secondary
and tertiary care are now more likely to see obese children and
adolescents in their everyday practice.
Definition
As in adult obesity, any definition of childhood overweight and
obesity needs to be able to define not only body fatness but also
the clinical relevance of this body fat. Body mass index (BMI) is
generally agreed to be the most appropriate proxy measure for
defining and diagnosing childhood obesity and overweight.6e8 In
childhood, because body fat and muscle mass alter with age and
differ between the sexes, BMI is meaningful only when it is
plotted correctly on age- and sex-specific BMI centile charts (UK
1990). All health professionals should use the UK 1990 BMI
centile charts for diagnosis and monitoring of treatment of
childhood obesity.6,7 The UK BMI centile charts are available
from Harlow Printing Ltd, South Shields, England.
Laura Stewart PhD RD RNutr is Team Lead, Paediatric Overweight Service
Tayside, NHS Tayside, and at the Children’s Weight Clinic, Edinburgh,
UK. Competing interests: none declared.
MEDICINE 39:1 42
Although there remains some disagreement on the precise
cut-off points to use for defining overweight and obesity on BMI
charts, both the SIGN 115 (2010) and NICE 43 (2006) guidelines
agreed on cut-off points in the UK of �91st centile as overweight
and �98th centile as obese,6,7 with SIGN 115 defining �99.6th
centile as severe obesity.7 These cut-off points have been shown
to be relevant to excess body fat and associated ill-health
consequences.6,7,9
Aetiology
An understanding of the complex aetiology of childhood obesity
is helpful to appreciate the changes required to manage obesity in
childhood. The causes of obesity are complex and multifactorial,
involving an interaction of our modern, obesogenic environment
and individual lifestyle choices. Because excess weight gain
occurs in a state of positive energy balance, increases in the
amount of calorie-dense foods eaten, and increases in screen
time (television, computer and video games) with a simulta-
neous decrease in the amount of physical activity undertaken by
children have been cited as reasons for the current epidemic.10,11
The understanding of the role of genetics in the predisposition
of some individuals to gain excess weight has improved in recent
years.12 However, for the vast majority of obese children, this
has not yet impacted on day-to-day clinical practice.13
Consequences
There is good evidence that childhood obesity persists (or tracks)
in to adulthood.14e17 The likelihood increasingmarkedly for obese
teenagers. A number of consequences of childhood obesity are
seen in childhood, adolescence and later in life. Clustering of
cardiovascular risk factors has been reported in children and
adolescents: high blood pressure, dyslipidaemia, abnormalities in
left ventricular mass and/or function, abnormalities in endothelial
function, andhyperinsulinaemia and/or insulin resistance. Abody
of evidence suggests that these cardiovascular risk factors are seen
in adults who were obese children or adolescents.13,14 There are
also instances of insulin resistance, type 2 diabetes and fatty liver
disease in obese adolescents.13,15,16 Psychological problems,
particularly in girls, have been reported in relation to low self-
esteem and behavioural problems. There are also long-term
consequences of social and economic effects, particularly in
women achieving a lower income.14,17 Table 1 gives a list of
consequences of obesity in children and adolescents that clinicians
should consider.
� 2010 Elsevier Ltd. All rights reserved.
OBESITY AND METABOLIC COMPLICATIONS
Assessment
If there are concerns that a child or adolescentmay be overweight or
obese, baseline measurements of weight and height should be
obtained and plotted on weight- and height-growth centile charts.
For children aged four years and under, the World Health Organi-
zation (WHO) growth charts should be used. BMI should be
calculated, and plotted at the correct age on the appropriate centile
chart for sex (UK 1990). The use of waist measurements in children
has gained support in recent years, and UK waist circumference
centile charts18 can be found on the flipside of the UK BMI centile
charts. However, there is no agreed cut-off point for defining level of
fat and thus those at health risk,9 and althoughwaistmeasurements
are a useful tool in monitoring progress in weight management,
they are not necessary for the current diagnosis of childhood
obesity.7,8
Particular consideration should be given to children and
adolescents who are obese but also of short stature, as this may be
an indication of a possible underlying endocrine cause of their
obesity, such as hypothyroidism, growth hormone deficiency,
Cushing’s syndrome or pseudohypoparathyroidism. Referral to
a paediatric endocrinologist should always be made for further
investigations.7,13 Young children, particularly those under 2 years
whohavehad a rapidweight gain, are severely obese and appear to
behyperphagicmayhave oneof the rare single genedefect causeof
their obesity and further investigations would be advisable.12 A
history of failure to thrive in infancy, and intellectual impairment
may alert the diagnosis of PradereWilli syndrome.
Discussing the subject of weight
There is a large body of evidence that shows many parents do not
recognize overweight and even severe obesity in their own
children.19e21 This can make the discussion of weight with
families daunting for clinicians and health professionals. Recent
work tells us that this should be approached directly, first with
the parents in an empathetic and non-judgemental
manner.20,22,23 Parents should be asked in a stepwise manner if
they consider their child’s weight a problem? Do they wish to do
any thing about their child’s weight? And what changes they feel
ready to make?22 Parents perceive a dialogue around their child’s
Consequences of childhood obesity2,13,14
C Cardiovascular disease
C Insulin resistance and type 2 diabetes
C Dyslipidaemia
C Hypertension
C Psychological and social morbidity
C Asthma
C Impaired fertility
C Orthopaedic e hips, ankles
C Breathing problems and sleep apnoea
C Fatty liver disease
C Some cancers
C Acceleration of puberty in both girls and boys
C Persistence of obesity into adulthood
Table 1
MEDICINE 39:1 43
physical activity levels as less threatening and less judgemental
of their parenting than questioning about their eating habits.23
Management
Management of childhood obesity is multifaceted, with inter-
ventions made complex by the interaction of the child or
adolescent with their parents and families. Parental weight is
known to influence the weight and lifestyle of the children in
a family, so the involvement of parents is fundamental to any
childhood weight-management programme.7,24 Recent guide-
lines and the Cochrane review25 on childhood obesity showed
a consensus on the following points:
� treatment should be commenced only when the parents are
ready and willing to make lifestyle changes
� treatment should be family based, with at least one of the
parents/carers involved.6,7,25
Table 2 summarizes the advice that should be given to children,
their parents and families. It is important to emphasis that changes
in total energy intake, screen time and physical activity are all of
equal importance in childhood weight management.7 Some
families are able to make positive changes when given simple
advice but the majority of children and parents will require to
attend an on-going group or individual programme over a number
of months. From current evidence, the optimal length of a weight-
management programme is unclear7 but programmes that include
the use of behavioural change tools would appear to be benefi-
cial.25 Clinicians should be aware of their local childhood weight-
management programmes and referral pathways.6,7
Outcomes
Weight maintenance in combination with increasing height
growth is an acceptable goal of treatment as this will lead to BMI
decreasing over time. For older adolescents, particularly those in
the very severe BMI range, weight loss may be required; if so,
a weight loss of 1e2 lbs per month would be advised.7 Most
research projects report outcomes as change in BMI standard
deviation scores (SDS). There is emerging evidence and debate
over the clinical significance of change in BMI SDS in children
and adolescents, particularly in relation to improvement in
insulin resistance, dyslipidaemia, and cardiovascular and
Recommended family lifestyle changes6,7,22
C Be physically active for 1 h per day (moderate to vigorous
intensity)
C Reduce screen time (sedentary behaviour, such as watching TV,
computers and playing computer games) to no more than 2 h per
day
C Encourage low-energy snacks (e.g. fruit, raw vegetables, a plain
biscuit)
C Avoid/cut down on high-energy foods such as crisps, chips,
chocolate, sweets
C Avoid grazing and keep food to meal times and small snacks
C Avoid sugary juice
C Parents should be positive about a healthy family lifestyle
Table 2
� 2010 Elsevier Ltd. All rights reserved.
OBESITY AND METABOLIC COMPLICATIONS
metabolic risk factors. At present, studies suggest a decrease in
BMI SDS ranging from �0.526 to �0.2527 may lead to an
improvement of risk factors in obese children.
Radical therapies
Practice points
C Weight issues should be discussed with the parent and child in
an empathetic and non-judgemental manner
C BMI centile charts should be used for the diagnosis of
childhood obesity
C Children with obesity who are of short stature should be
referred for further investigation
C Treatment programmes should target decreases in total
energy, reduction in screen time and increases in physical
activity levels
C Weight maintenance leading to a decrease in BMI is an
acceptable outcome.
Both the NICE 2006 and SIGN 2010 guidelines recommended that,
in certain circumstances and under close supervision, anti-obesity
drugs and bariatric surgery could be considered in adolescents.
Anti-obesity drug therapy could be considered for prescription to
obese adolescents who are attending a specialist weight-manage-
ment clinic.6,7 SIGN 115 further recommended that anti-obesity
drugs should be prescribed only for adolescents with severe
obesity (BMI >99.6th percentile) and with co-morbidities.7 Pres-
ently orlistat is the only anti-obesity drug available for use in the
UK, and is not licensed for use in children. It functions primarily by
preventing the absorption of fats, thereby decreasing the available
energy from the diet. It is recommended that patients are regularly
reviewed throughout the period of use, with carefulmonitoring for
side effects.7 Although in adults orlistat does not cause hypo-
vitaminosis, it does reduce circulating levels, so early vitamin
supplementation may be indicated for children.
Although bariatric surgery in children and adolescents is
uncommon in the UK, both guidelines suggest that bariatric
surgery for weight loss could be considered for post-pubertal
adolescents with very severe obesity and co-morbidities, and
stress that surgery should be undertaken only in a centre of
excellence in adult bariatric surgery.6,7 Since long-term side effects
of bariatric surgery in adolescents are unknown it is highly
desirable that follow-up should be for life. A
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