Childhood obesityDr Michal AjzensztejnThe Evelina London Children’s Hospital July 2014

Overview

Definition

Size of the problem?

Aetiology

What is the cause for concern?

ManagementpreventionInvestigationTreatment

Definition of obesity

Gold standard is body composition

MRI / Dexa / bioimpedence (proxy)

Waist circumference

BMI = Kg/M²

A child's weight status is determined using an age- and sex-specific percentile for BMI rather than the BMI categories used for adults because children's body composition varies as they age and varies between boys and girls.

DefinitionObesity expert

committee- pediatrics 1998

Overweight: 85-95th Centile

Obese: >95th Centile

International Obesity Task Force

Overweight>91st centile

Obese>99th centile

International obesity task force definition (IOTF) Cole et al BMJ 2000;320:1

Centiles for body mass index for British males and females. Centile curves are spaced two thirds of z score apart. Also shown are body mass index values of 25 and 30 kg/m2 at age 18, with extra centile curves drawn through them

Types of obesity in childhood

Primary

SecondaryEndocrine Hypothyroidism Cushings syndrome pseudohypoparathyroidismHypothalamic MonogenicSyndromes

The scale of the problem WHO- childhood obesity one of the most serious global public health

challenges of 21st century.

The National Child Measurement Program (CCMP) measures the height and weight of ~1M school children in England/yr. Latest figures show: 14.4% of children aged 10-11yrs – obese 18.9% of children aged 10-11yrs- overweight 9.3% of children aged 4-5yrs – obese 13% of children aged 4-5yrs - overweight.

1/3rd of 10-11yrs old + >1/5th of 4-5 yr olds were overweight or obese.

According to the National Audit Office- weight problems costs the Health Service £500million in consultations, drugs and other therapies.

Obesity causes 30,000 deaths a year.

Research from British Heart Foundation suggests children and young people could die from complications of obesity before their parents

By 2030 up to 48% of men and 43% of women in the UK could be obese if current trends in rise of obesity continue

Trends in adult prevalence of obesity (BMI > 30kg/m2)

Trend in childhood obesity US children 1971-2006

Causes of primary obesity Interaction between genetic predisposition (50-

90%)& environment affecting food intake and energy expenditure

Twin studies offer some insight into the genetics of common obesity Data from > 25,000 twin pairs and 50,000

biological and adoptive family members Estimates for mean correlations for BMI are:

0.74 for monozygotic twins, 0.32 for dizygotic twins 0.25 for siblings 0.19 for parent–offspring pairs, 0.06 for adoptive relatives 0.12 for spouses

Environmental factors Increase risk

History of SGA- increased rates of obesity and metabolic syndrome

Poor infant feeding

Reduced energy expenditure

Social concerns- fear to let children play outside

Parental obesity/ eating disorders

Increased high fat / carb food intake

Increased sedentary lifestyle Screen time (TV, computers, phones, ipad)

Protective factors

Family meals

Self esteem

Breastfeeding

Foetal origin hypothesis “Barker Hypothesis”

‘Foetal undernutrition in middle to late gestation leads to disproportionate foetal growth’ programmes later coronary heart disease’

‘The most unfavourable outcome is thinness at birth followed by a rapid increase in body weight’

Foetal programming

The way the mother prepares the foetus for the world in which it will be born

A communication through placental nutrition

Nutrition may alter the expression of maternal genes involved in foetal growth – ‘imprinting’ – gene methylation

The ‘Thrifty Phenotype’ - a mismatch between fetal programming and the environment

Genetics

Polygenic inheritance pattern with 2 subtypes (generalised and abdominal) multiple polymorphic single genes likely involved no genes for common obesity identified very rare monogenic forms of obesity

Gene defects ob/ob mouse – genes mutant – leptin deficient db/db mouse- mutation in leptin receptor POMC/ MC4R / neuronal insulin receptor mutations

Genetics Of Obesity Study (GOOS) Cambridge

Sadaf Farooqi and Stephen O’Rahilly

BMI >4SDs for age /sex

Consanguineous or

FH of early onset < 10 yrs

Over 3000 samples analysed

Monogenic causes of obesity

Leptin deficiency

Leptin receptor deficiency Hypogonadotrophin hypogonadism and other

pituitary hormone abnormalities

Prohormone convertase1 (PC1) defect Abnormal glucose tolerance Hypocortisolism, hypog/hypog.

Melanocortin – 4-receptor defect

POMC deficiency Red hair, adrenal insufficiency

PPARγ defect

GhrelinHunger-stimulating peptide

produced by P/D1 cells in lining of the fundus of stomach

Ghrelin receptors are expressed in the pituitary, stomach, intestine + pancreas.

Gherlin levels increase before meals and decrease post meals

When a person loses weight- ghrelin levels , which causes food consumption and weight gain

When a person gains weight ghrelin levels, causing a in food consumption and weight loss

Leptin "satiety hormone"Leptin is made by adipose tissue, it acts via

receptors in the brain (LRb) to regulate energy balance and satiety.

Leptin stimulates the hypothalamus to give us the sensation of satiety resulting in decreased appetite and increases metabolism to aid wt loss.

The less fat you have, the less leptin you produce, resulting in increased appetite and decreased metabolism to enables wt gain.

However if you have increased fat stores there is increased leptin, which can lead to leptin resistance. So despite lots of leptin, appetite is not suppressed, metabolism is slowed down resulting in increased appetite and wt gain.

Medical causes of obesityEndocrine

HypothyroidCushing syndromePseudohypoparathyroidismPCOS

MonogenicLeptin deficiencyPOMC deficiencyMC4R mutation 5% BMI>3 or 4SD

Hypothalamic Eg tumours/craniopharyngioma

SyndromesPrader-WilliBardel-BiedlCohenCarpenter

Why is childhood obesity getting so much attention!

Tracking into adult life( 60%)

Metabolic syndrome (IRS)

Secondary effects

Implications of childhood obesity

Obese children become obese adults

Comorbidities: Hypertension Metabolic syndrome: hyperlipidaemia PCOS Non-alcoholic fatty liver Insulin resistance/ impaired fasting and glucose tolerance Type

2 DM Slipped femoral capital epiphysis/ joint pain Sleep apnea Asthma Benign raised intracranial pressure

Emotional + psychological effects of being overweight Teasing/ bullying Low self esteem Anxiety Depression

Insulin resistance SyndromeMetabolic syndrome (syndrome X)

Central obesity (apple shape)

Hypertension

Raised triglycerides

Low HDL

Insulin resistance PCOS

Steatohepatitis

Glomerulonephritis

Atherosclerosis

Impaired glucose tolerance

Insulin resistance syndrome

A velvety brown change to the skin

Mostly in neck, axilla, groin

Looks like dirt but doesn’t wash off!

Usually obese

Almost always have insulin resistance

Leads to Type 2 diabetes

Local problem

In 2000, the first cases of Type 2 diabetes in children were diagnosed in overweight girls aged 9 to 16 of Pakistani, Indian or Arabic origin in the UK.

Nationally incidence of type 2 diabetes amongst children is 1.5%

In Lambeth and Southwark the incidence of type 2 is closer to 5%.

Obesogenic Environement

Family• Excess weight in parents• Breast feeding practices

• Parent’s health• Much Sedentary activity e.g

TV, computers etc.• Knowledge

• Budgeting, shopping and cooking skills• Genetic predisposition

Education & information• School lessons

• Lifestyles• Nutrition• Cooking

• Media messages• Fashions

• Body image• Cultural beliefs

• Conflicting information

Sports & Leisure• Lack of school facilities• Few local playing areas• Widely available indoor-

passive entertainment• Unsafe streets

• Few cycle routes

Social + economic inequalities in diet and physical activity

ManagementPrimary Prevention

Community based weight management service

Tertiary obesity serviceSevere obesityObesity with co-morbidities

Primary Prevention

Ante-natal care of the obese mother

Use of appropriate standardsWHO-UK Growth charts

Focus on early intervention (under 5s)Education of midwives and HVsBetter infant feeding advicePromotion of breast feedingBetter management of SGA/IUGR

infants

Community based services

Not just an issue for health workers-

community-wide approach

Input from education, LAs, sports bodies and voluntary groups

Specialised school nurse An Information Resource Educators Give basic dietary advice Risk assessment for referral

MEND- Mind, Exercise, Nutrition, Do it / Ready Steady Go

Planning permission- locality of sweet shops / fast food shops to schools

Media + Advertising companies- also have a duty

Tertiary level

Severe ‘morbid’ obesity

Pre-diabetic, insulin resistance, Type 2 diabetes

Adverse FH diabetes, ↑BP, ↑cholesterol, Ischaemic heart disease

Health co-morbidities CardiacRenalNeurological/muscular disordersSteroids induced

Monogenic / syndrome

Tertiary serviceMulti-disciplinary team

Psychologist / Family therapyDieticianSports trainerPaediatrician?Social worker

An initial team assessmentMotivational Interviewing skillsUnderstanding eating behavioursFuller family analysis

Classification for Investigation

Primary obesity with no family risk

Primary obesity with adverse family risk or signs/ suspicion of hyperinsulinism/ type II diabetes

Suspicion of secondary obesity/ genetic cause

InvestigationsSimple obesity with no adverse family

risk

If well grown in height and normal on examination: liver & renal function +/- liver USSTFTFasting lipidsFasting glucose/insulin blood pressure (ambulatory if possible)

Simple obesity with family risk history or clinical suspicion of hyperinsulinismAs above plusOGTT with insulins

Secondary / genetic cause Investigate cause Eg UFC for cushings. Overnight

Dex suppression test Genetics for GOOS study

Who to treat?Those with BMI > IOTF 30

Those with BMI >IOTF 25 with strong family history diabetes/early CVD impaired glucose tolerance

Age:Rx should focus on >8 yrsThose obese < 8yrs with obese parents

IOTF- international obesity task force

Treatment

Treatment of obesityDietDrugsExercise programsPsychological approachesMulti-disciplinary approachesSurgery- Bariatric surgery /

intragastric balloon

Treatment of obesity complications

Treatment targets

5% loss is standard adult weight loss target10% is doing very well!but losses are maintained better in children

than adults

Weight maintenance in growing children

Imperative to start Rx before growth ceases

Treatment of Choicecomprehensive treatments

including:behavioral modification proceduresdietary interventionan exercise programreduction of sedentary behavioursfamily centred

motivational enhancement

Drugs

Drug trials for obesity in children & adolescents

Extremely few published

Drugs not licensed

We cannot assume risks and benefits same as in adult

What’s availableOrlistat – binds intestinal and pancreatic

lipase and reduces dietary fat absorption by 30%

2.5 kg to 3.0 kg over 3-4 yrs. Compared with placebo

Reduces absorption of fat soluble vitamins

Metformin – useful in diabetes, impaired glucose intolerance and possibly insulin resistance

May improve cardiovascular outcome and reduce risk of PCOS/ metabolic syndrome

Surgery

UK: NICE guidelines recommend consideration of surgery for young people in exceptional circumstances

“Surgery...has the best chance of significant weight loss, reversal or improvement of current co-morbidities, and reduction of risk for future co-morbidities” Brown &Inge 2009

Criteria for Bariatric Surgery in children BMI of 40 (kg/m2) or more - OR

BMI >30 + other significant disease

All non-surgical measures have failed for at least 6 months

Receiving intensive management in a specialist service

Generally fit for anaesthesia and surgery

Commitment to long-term follow-up

Physiological and psychological maturity

Bariatric Surgery

Types Gastric banding Gastric bypass Gastric sleeve surgery

No surgery without risk- High risk group

Post surgical complications

Long term follow up

Long term supplement therapy

Intragastric balloon Rx?

Less invasive

No long term complications

However are the results as sustainable?

The Evelina London Children’s Hospital obesity service Still in the job planning phase

Will integrate community to tertiary level care

Bridge between medical and surgical intervention

Provide intragastric balloons

Multidisciplinary team: Psychological/ family approach Dietician Sport/ activity Nurse Doctor Speciality care: sleep study, orthopaedic, referral to King’s for

liver and bariatric surgery

Thank youQUESTIONS?