Obesity - An Atlas of Investigation and Management

119 Pages·2011·9.88 MB·English

by  BS Aditya

An Atlas of Investigation and Management
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A unique illustrated guide, tackling a complex condition that
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covers aetiology through to assessment, management and n
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prevention. Associated comorbidities and complications are Paraventricular nucleus g
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clearly illustrated, with covering clinical presentations across Intestine CCK Cerebral cortex
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different age groups. Brain nuclei
PYY3-36
POMC Foreword by WpT James
Hypothalamic
this book leads the reader through an introductory discussion Insulin arcuate nucleus Feeding
Pancreas neurons Metabolic rate
of the definitions of obesity and its epidemiology. there follows Gastric emptying
a detailed section on pathophysiology and aetiology, tackling
genetic predisposition and appetite regulation, in addition to
common environmental and lifestyle factors and ethnicity.
the authors also devote a section to the much neglected area
of management, approaching this area by defining the need to
effectively assess the causes of the condition in the patient, giving
advice on differential diagnosis, diet and exercise, behavioural
therapy, and clinical interventions. the atlas concludes with
a summary of hospital care for the morbidly obese, and looks
Author Wilding & Aditya
at promising future pharmacological therapies as well as Title Obesity – Atlas of
Investigation .......
preventative measures. Fig. no. 2.4
Date 01/02/11
ISBN 978 1 84692 027 1
Related titles: Graeme Chambers
email: [email protected]
tel: [phone]
Clinical Challenges in Diabetes, AH barnett
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IsbN 978 1 84692 054 7
b
Primary Hyperlipidemias: Atlas of Investigation and Diagnosis,
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Problem Solving in Cardiovascular Risk, MA Crook, R Minhas,
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Therapeutic Strategies in Diabetes, CDA stehouwer, NC schaper
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Obesity cover.indd 1 04/05/2011 13:25
An Atlas of Investigation and Management
OBESITY
BS Aditya, MRCP
Consultant Physician
Diabetes and Endocrinology Department
University Hospital Aintree
Liverpool, UK
JPH Wilding, DM, FRCP
Professor of Medicine
University of Liverpool
Honorary Consultant Physician
Head of Department of Obesity and Endocrinology
University Hospital Aintree
Liverpool, UK
Foreword by
W Philip T James, CBE, FRSE, MD, DSc
President, International Association for the Study of Obesity (IASO)
Honorary Professor of Nutrition
London School of Hygiene and Tropical Medicine
London, UK
CLINICAL PUBLISHING
OXFORD
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© Atlas Medical Publishing Ltd 2011
First published 2011
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ISBN-13 978 1 84692 027 1
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The publisher makes no representation, express or implied, that the dosages in this
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clinical procedures with the most up-to-date published product information and data
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Project manager: Gavin Smith, GPS Publishing Solutions, Herts, UK
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Printed and bound by Marston Book Services Ltd, Abingdon, Oxon, UK
Contents
Foreword vii
Preface ix
Acknowledgements x
Abbreviations xi
1 Obesity 1
2 Pathophysiology and aetiology of obesity 19
3 Associations and complications of obesity 39
4 Management of obesity 67
5 Miscellaneous 89
Index 105
vii
Foreword
JohnWildingandSumerAditya’sbookhascomeatatime experienceofhowbesttocommunicatewhataresometimes
whenthereisanoverwhelmingfocusonobesity,withhun- quitecomplicatedtopics.
dredsofnewandoftenconflictinganalysesrelatingtoits The importance of new approaches to obesity man-
significance,rangingfromwhethertherearesimplemethods agementhasclearlygoneuptheprioritylistforallthose
forassessingbodyfatnesstohowmuchsignificanceshould involvedinhealthcare.ThisinpartstemsfromtheMinisters
begiventothemanyvariedconsequencesofweightgain.An ofHealthmeetinginIstanbulinNovember2006,when
evenbiggermuddleariseswhenconsideringhowtomanage 53nationswerecalledonbytheEuropeanRegionofthe
overweightandobesepatients,withanextradimensionnow WorldHealthOrganisationtodosomethingpracticalabout
beingaddedbytherecentwithdrawaloftwopotentiallyvery theeconomicallyunsustainableexplosionofobesity.For
valuabledrugswhichaidedlongtermweightmanagement. thefirsttime,theMinistersnotonlyagreedthatpreventive
Foranyhealthcareprofessional,whetherbasedinprimary initiativeswereneeded,butformallyundertooktotackle
orsecondarycare,theprofusionofspecificclaimsand theexistingchallengeofhundredsofmillionsofadultsand
analysesrelatingtoobesityisdaunting.Thisleadstoasense childrenwhoneededassessmentandhelpincopingwith
offrustrationandthesubsequentavoidanceofobesityasan theiroverweightandobesity-relatedproblems.Sincethen
issuethatoughttobedealtwithaspartofgeneralclinical newanalyseshaveclearlyshownthatdoctorsworkingwith
care.Forallprofessionals,includingdoctors,nutritionists, additionalhelpcanprovidebyfarthemostcost-effective
dietitiansandexercisespecialists,aswellasthepublicanx- meansofcopingwiththenationalhealthburden.Thisbook
ioustounderstandtheissues,thereisafurtherproblemin providesthebasisforanewapproachtotheappropriate
thatsomuchofthemedia’sattentionistakenupwithquirky assessmentoftheoverweightpatientandacoherentpro-
ideasandisolatedfindings.Onthisbasisitisnowonderthat gressiveapproachtoimprovingtheircareandwell-beingon
confusionreignsastheepidemicgrowsworse. alongtermbasis.Onlytenyearsagoobesitywasdescribed
Thisbookhasclearlybenefitedfromtheauthors’many asthebiggestunrecognisedpublichealthproblemconfront-
yearsofpracticalexperienceinmanagingobesity,andin ingtheworld:theauthorsaretobecongratulatedonprovid-
teachingbothmedicalstudentsandpostgraduatesfrom ingapracticalbookthatmayhelphealthcareprofessionals
awiderangeofdisciplineswhohavebeenattendingthe tacklethismajordisorder.
annualLiverpoolpostgraduatecourseinobesitymanage-
ment.Theuseofmultiplediagramstoillustratethediffer- PhilipJames
entconceptsineachchapterclearlycomesfromhands-on April, 2011
ix
Preface
Weareinthemiddleoftwinepidemicsofobesityandtype needstobemulti-dimensional.Wehavediscussedtheroleof
2diabetes,whicharecertainlyinter-related.Theawareness lifestylemodificationwithdetailsofcommontypesofdietary,
ofobesityasamajorhealthcareconcernhasgrownrapidly exerciseandbehaviouralinterventions.Therehasbeena
inthelastdecadeandobesityhasbeenaptlylabelledas‘the hugeinterestinpharmacologicaltreatmentofobesitybut
millenniumdisease’.Obesityisnotonlyoneofthemajor thecurrentoptionsarelimited.Wehavehighlightedthepast
modifiableriskfactorsforcardiovasculardiseaseanddeath, experiencesandthedifficultiesinfindinganeffectiveyetsafe
butalsocontributestothedevelopmentofmanyother therapeuticagent.Theriskofadverseeffectshaslimitedthese
serioushealthdisorderssuchastype2diabetes,metabolic optionsandhasleadtowithdrawalofpreviouslyapproved
syndrome, obstructive sleep apnoea, respiratory disease, agentsthatinitiallyshowedgreatpromise.Bariatricsurgery,
musculoskeletaldiseaseandmanycommoncancers.Aswell althoughanexpensiveoptionwithlimitedavailability,has
asthesephysicalco-morbidities,obesityisassociatedwith becomeverypopularinthelastdecadeandwehavediscussed
asignificantburdenofpsychologicaldiseaseandadverse thetypesofproceduresusedintheworldtoday.Long-term
socialconsequences,resultinginimpairedqualityoflife, dataabouttherisksandbenefitsofeachsurgerytypearepro-
reducedproductivityandadditionalcoststoalreadyover- vided,alongwithdetailsofprognosisandmortality.
burdenedhealthcaresystems.Thecosttosocietyforcur- Tacklingthisepidemicrequiresstrategicplanningand
rentandfuturegenerationsislikelytobeimmense. implementationatvariouslevels.Wehavediscussed,inthe
Despitetheincreasingawarenessoftheseriousnessand finalsection,thebarriersandsolutionstoeffectivecareof
scaleoftheobesityepidemic,currentlyavailableeducational obesity and prevention of this modern, lifestyle-related,
resourcesandmaterialavailablearelimited.Thisatlashasbeen publichealthconcern.Obviouslythereisagreatdealof
producedwiththeaimofprovidinganaccessibleandpracti- interestinobesityamongstresearchers,clinicians,thephar-
calsummaryoftheepidemiology,aetiology,complications maceuticalindustryandsurgeonstounderstandthepatho-
andmanagementofobesity,placedinthecontextofrecent physiologyandconsequencesofobesityandtodevelopsafe
scientificandclinicaldevelopments,whichshouldbeessential andeffectivetreatmentofthiscommondisorder.Wehave
backgroundinformationforeveryoneinterestedinobesity. summarisedsomeoftheadvancesinthisarea,withparticu-
Theinitialsectiondescribesthecommonmethodsofdefin- larinterestinfutureofobesitypharmacotherapy,genetic
ingandstratifyingobesityandbrieflydiscussestheepidemiol- research, functional neuro-imaging and have discussed
ogyofthisconditionwhichwasinitiallyconsideredadisease newerbariatricsurgicalproceduresandtechniqueswhich
ofaffluentsociety,butisnowrecognisedtobeauniversal promisetobemoreeffectiveandlessinvasive.
problem, increasingly affecting the developing world and Wehopethisatlaswillprovideup-to-dateandeasily
lowersocio-economicclasses.Thepathophysiologyandaeti- accessibleinformationtopeoplefromvariousdisciplines
ologyofobesityiscomplexandmulti-factorial;wehavedis- whoareinterestedinobesity.Theatlasisfullofeasyto
cussedenergybalance,appetiteregulation,geneticinfluence understandfiguresandtableswithconcisewrittenmaterial
andtheeffectofmodernlifestyleandenvironmentalfactors. whichwillbeofusetoclinicians,alliedhealthprofessionals
Thegrowinginterestsinfoetalandinfantoriginsofobesityin andstudentsalike.Allsectionsintheatlasarereferenced,
additiontosecondarycausesofobesityarealsohighlighted. toeasilydirectreaderstowardsfurtherreadingmaterial
Wehavediscussedtheassociationsandcomplicationsof andrecentscientificdevelopments.Moreworkisurgently
obesitywhichareimmenseandsignificant.Overthelastfew neededtotacklethishugeepidemicandwehopethisatlasis
decades,bodyweighthasbeenidentifiedasamajorriskfactor onesmallstepinthatdirection.
affectingalmostallbodyorgansandphysiologicalsystems.We
havesummarisedsomeofthelatestresearchinthisfield,with BhandariSumerAditya
appropriatesfiguresandtables,andalsoprovidedreferences JohnPHWilding
forfurtherreading.Obesitymanagementisoftendifficultand April 2011
x
Acknowledgements
Dr Paul Albert
ConsultantinRespiratoryMedicine
UniversityHospitalAintree
Liverpool,UK
Dr Daniel Cuthbertson
SeniorLecturerandHonoraryConsultantPhysician
UniversityHospitalAintree
Liverpool,UK
Dr Christina Daousi
SeniorLecturerandHonoraryConsultantPhysician
UniversityHospitalAintree
Liverpool,UK
xi
Abbreviations
5-HT 5-hydroxytryptamine/serotonin EDJT endoluminalduodeno-jejunaltube
ADA AmericanDiabetesAssociation EMA EuropeanMedicinesAgency
AgRP Agouti-relatedpeptide FDA USFoodandDrugAdministration
AHA AmericanHeartAssociation FEV  forcedexpiratoryvolumein1second
1
AMI acutemyocardialinfarction FFA freefattyacid
a-MSH alpha-melanocyte-stimulatinghormone fMRI functionalmagneticresonanceimaging
Apo apolipoprotein FPG fastingplasmaglucose
ARCN arcuatenucleus FTO fatmassandobesity-associatedgene
BMI bodymassindex FVC forcedvitalcapacity
BMR basalmetabolicrate GDM gestationaldiabetesmellitus
BOLD bloodoxygenlevel-dependent GIANT GeneticInvestigationofAnthropometric
BP bloodpressure Traitsstudy
BPD biliopancreaticdiversion GFR glomerularfiltrationrate
CART cocaineandamphetamine-regulated GI gastrointestinal/glycaemicindex
transcript GIR glucoseinfusionrate
CBF cerebralbloodflow GLP-1 glucagon-likepeptide-1
CBT cognitivebehaviourtherapy GLUT4 glucosetransporterprotein-4
CCK cholecystokinin HbA  glycosylatedhaemoglobin
1c
CDC CentersforDiseaseControland HDL high-densitylipoprotein
Prevention HDL-C high-densitylipoproteincholesterol
CHD coronaryheartdisease HES HospitalEpisodeStatistics
CI confidenceinterval HF heartfailure
CPAP continuouspositive-airwaypressure HOMA  homeostasismodelofassessment–insulin
IR
CRESCENDOComprehensiveRimonabantEvaluation resistance
StudyofCardiovascularEndpointsand HR heartrate
Outcomes HTN hypertension
CRF chronicrenalfailure IARC InternationalAgencyforResearchon
CRH corticotrophin-releasinghormone Cancer
CRP C-reactiveprotein IASO InternationalAssociationfortheStudyof
CT computedtomography Obesity
CV cardiovascular ICAM-1 intercellularadhesionmolecule-1
CVD cardiovasculardisease ICD-10 InternationalStatisticalClassificationof
DB double-blind DiseasesandRelatedHealthProblems,
DBP diastolicbloodpressure 10thRevision
DEXA/DXA dualenergyX-rayabsorptiometry IDF InternationalDiabetesFederation
DJB duodenal-jejunalbypass IGB intragastricballoon
DMN dorsomedialnucleus IGT impairedglucosetolerance
DS duodenalswitch IL-6 interleukin-6
DSM-IV DiagnosticandStatisticalManualof INSIG2 insulininducedgene2
MentalDisorders,4thEdition IOTF InternationalObesityTaskForce
DVT deepveinthrombosis IT ilealinterposition
ECS endocannabinoidsystem ITT intenttotreat
xii Abbreviations
LAGB laparoscopicadjustablegastricbanding POMC proopiomelanocortin
LDL low-densitylipoprotein PP postprandial
LDL-C low-densitylipoproteincholesterol PVN paraventricularnucleus
LEPR leptinreceptor PVR peripheralvascularresistance
LH luteinisinghormone PYY peptideYY
LHN lateralhypothalamicnucleus QOL qualityoflife
LOCF lastobservationcarriedforward QTL quantitativetraitlocus
LSCS lowersegmentCaesareansection RAAS renin–angiotensin–aldosteronesystem
LVH leftventricularhypertrophy RAPSODI RimonabantinPrediabeticSubjectsto
MAO monoamineoxidase DelayOnsetofType2Diabetesstudy
MC4R melanocortin-4receptor RBP-4 retinolbindingprotein-4
MCH-1 melanin-concentratinghormone-1 rCBF regionalcerebralbloodflow
MCP-1 monocytechemoattractantprotein-1 RIO-Diabetes RimonabantinObesity–Diabetesstudy
MET metabolicequivalent RIO-Europe RimonabantinObesity–Europestudy
MI myocardialinfarction RIO-Lipids RimonabantinObesity–Lipidsstudy
MRFIT MultipleRiskFactorInterventionTrial RIO-North RimonabantinObesity–NorthAmerica
MRI magneticresonanceimaging  America study
MRS magneticresonancespectroscopy ROS reactiveoxygenspecies
Na sodium RR relativerisk
NASH non-alcoholicsteatohepatitis RYGB Roux-en-Ygastricbypass
NCEP-ATPIII ThirdReportoftheNationalCholesterol SB single-blind
EducationProgram SBP systolicbloodpressure
ND notdetermined SCOUT SibutramineCardiovascularOutcomestrial
NEAT non-exerciseactivitythermogenesis SEM standarderrorofthemean
NEFA non-esterifiedfattyacids SERENADE StudyEvaluatingRimonabantEfficacyin
NFS NationalFoodSurvey(UK) Drug-NaiveDiabeticPatients
NHANES NationalHealthandNutrition SG sleevegastrectomy
ExaminationSurvey SHBG sexhormone-bindingglobulin
NHLBI NationalHeart,LungandBloodInstitute SHIELD StudytoHelpImproveEarlyevaluation
NOTES naturalorificetransluminalendoscopic andmanagementofriskfactorsLeadingto
surgery Diabetes
NP natriureticpeptide SN supra-opticnucleus
NPY neuropeptide-Y SNP singlenucleotidepolymorphism
OA osteoarthritis SNS sympatheticnervoussystem
ODST overnightdexamethasonesuppressiontest STORM SibutramineTrialofObesityReduction
OFC orbitofrontalcortex andMaintenance
OGTT oralglucosetolerancetest TBW totalbodywater
OHS obesityhypoventilationsyndrome TG triglyceride
OSA obstructivesleepapnoea TNF-a tumournecrosisfactor-alpha
OSAS obstructivesleepapnoeasyndrome UWW underwaterweighing
OTC over-the-counter VLCD verylowcaloriediet
PAF populationattributablefraction VLDL verylow-densitylipoproteincholesterol
PAI-1 plasminogenactivatorinhibitor-1 VMN ventromedialnucleus
PAR populationattributablerisk WC waistcircumference
PCOS polycysticovariansyndrome WHO WordHealthOrganization
PET positronemissiontomography WHR waist-to-hipratio
PFC prefrontalcortex XENDOS XENicalinthePreventionofDiabetesin
PHLA post-heparinlipolyticactivity ObeseSubjects
Chapter 1
1
Obesity
Definition, classification, and
Body Mass Index (BMI) = Weight in kg / Height in metres2
measurements
Body Mass Index (BMI) = Weight in pounds ¥ 703 /
Height in inches2
Obesity can be defined in simple terms as the excessive
1.1 Calculation of BMI.
amount of body fat associated with an increased risk of
medical illnesses and premature death. It is the result of
Markers of increased risk are as follows:
a complex process of undesirable positive energy balance
and weight gain. Although the total body fat mass is 1. Waist circumference >102 cm (40 inches) in men and
important, it is now recognized that the localization >88 cm (35 inches) in women.
of excess fat, particularly intra-abdominal and visceral 2. Weight gain of ≥5 kg since age 18–20 years.
fat, has a stronger correlation with risk of diabetes and 3. Poor aerobic fitness.
cardiovascular disease (CVD).1 The risk of coexisting 4. Certain ethnic groups (e.g. South Asian, Pacific islanders,
diseases associated with obesity is also affected by a range Pima Indians).
of factors, including nature of the diet, ethnic group, and
activity level. Although BMI measurements can sometimes be
Body mass index (BMI) is a simple index of ‘weight-for- misleading (e.g. muscular individuals, old age, ethnic
height’. The calculation of BMI is shown in 1.1. Clinically, variations), there appears to be a good correlation between
‘obesity’ is defined as a BMI of ≥30 kg/m2. Overweight is BMI and the percentage of body fat.4 There is also a strong
defined as a BMI of between 25 and 30 kg/m2 (Table 1.1). correlation between BMI and mortality (1.2).5
Table 1.1 Classification of obesity in adults according to BMI and risk of obesity-related diseases2,3
Obesity class BMI (kg/m2) Associated risk
Underweight <18.5 Low (but risk of other health problems increased)
Normal 18.5–24.9 Normal
Overweight Pre-obese 25.0–29.9 Increased
Obesity I 30.0–34.9 Moderate
II 35.0–39.9 Severe
Extreme obesity III ≥40.0 Very severe