epidemic

Review

TheObesityEpidemicandItsImpactonHypertension

ThangNguyen,MD,FRCPC,,MD,PhD,FRCPCb

aDivisionofCardiology,CardiacPreventionandRehabilitation,StMichael’sHospital,Toronto,Ontario,Canada

bDepartmentsofMedicine,BiochemistryandMolecularBiology,andCardiacSciences,JuliaMcFarlaneDiabetesRearchCentre,University

ofCalgary,Calgary,Alberta,Canada

ABSTRACT

Globalobesityrateshaveincreadsteadilyinbothdevelopedand

emergingcountriesoverthepastveraldecadeswithlittlesignsof

1.5billionpeopleworldwideareoverweightor

obeandover40millionchildrenundertheageof5areoverweight.

Obesityisassociatedwithincreadmorbidity,disability,andprema-

turemortalityfromcardiovasculardia,diabetes,cancers,and

sonalandsocietalhealthandeco-

nomicburdenofthispreventablediapoariousthreattoour

yisamajorriskfactorforhypertensionandcardio-

loss,throughhealthbehaviourmodification

anddietarysodiumrestriction,isthecornerstoneinthetreatmentof

cotherapyandbariatricsurgery

forobesityareadjunctivemeasureswhenhealthbehaviourinterven-

sful

managementofoverweightandobepersonsrequiresacomprehen-

sive,multifacetedframeworkthatintegratespopulationhealth,public

health,andmedicalhealthmodelstodismantletheproximaland

RÉSUMÉ

Letauxd’obésitéglobaleaaugmentédemanièrerégulièredansles

paysdéveloppétlespaysémergentsaucoursdesdernièresdécen-

nies,toutenmontrantdelé1,5

milliarddepersonnesdanslemondesontpréobèsouobès,et

plusde40millionsd’enfantsdemoinsde5anssontpréobès.

L’obésitéestassociéeàuneaugmentationdelamorbidité,de

l’incapacitéetdelamortalitéprématuréeenraisondesmaladies

cardiovasculaires,dudiabète,descancertdestroublesmuscu-

losquelettiquengendréépersonnelleetsocialeainsiquele

fardeauéconomiquedecettemaladieévitablepontunsérieux

problèmeànossociétés.L’obésitéestunfacteurderisquemajeurde

l’edepoids,

parlamodificationdescomportementsdesantéetparlarestriction

ensodiumalimentaire,estlapierreangulairedansletraitementde

l’hypertensionliéeàl’obésité.Lapharmacothérapieetlachirurgie

bariatriquesontdesmoyensauxiliaireslorsquelesinterventionn

matièredecomportementdesanténemènentpasauxobjectifsde

Obesityhasreachedepidemicproportionsgloballyandhas

becomeamajorpublichealthconcern.1In2008anestimated

1.5billionadultsworldwidewereoverweightand500million

an40millionchildrenundertheageof5

areoverweight.2,3Obesityrateshavemorethandoubledsince

1980,with1in10oftheworld’sadultpopulationnow

obe.2,3Adiposity,orexcessbodyfat,isassociatedwithin-

creadmorbidity,disability,andprematuremortalityfrom

cardiovasculardia(CVD),diabetes,cancers,andmusculo-

odymassindex(BMI)(calculatedas

weight[kg]/height[m2])asananthropometricmeasureofad-

iposity,each5unitsabovetheoverweightcategory(BMIϾ

25)isassociatedwithapproximately30%higheroverallmor-

talityand40%higherforcardiovascularmortality.4Depend-

ingontheverityofobesitythelifeexpectancyofoverweight

ly3

milliondeathsannuallyhavebeenattributedtoobesity.2

Theexcessmortalityamongoverweightandobe(defined

asBMIϾ30)peopleisduemainlytocardiovascularcaus.

AccordingtotheWorldHealthOrganization,morethana

thirdoftheworld’sdeathscanbeattributedtoasmallnumber

he5leadingriskfactorsarehighblood

pressure(BP),tobaccou,highbloodsugar,physicalinactiv-

ity,overweight,andobesity.2HighBP,obesity,andphysical

inactivityeachaccountedfor395,000,216,000,and191,000

preventabledeathsin2005intheUS.5Exceptfortobaccou,

4ofthe5riskfactorsareinterrelated—bothhypertension

andhighbloodsugarcouldbeattributabletounhealthy

behaviourssuchasfoodoverconsumptionandphysicalin-

activity,whichinturnmayleadtothedevelopmentofover-

,obesityhaclipdcigarette

smokingastheleadingpreventablecauofdeathandshort-

enedlifeexpectancyintheUS.6

Hypertensionisacommonfeatureprentinalargepro-

rrelatedwith

thedegreeofobesityandgreatlyexaggeratestheriskofstroke,

ReceivedforpublicationDecember8,edJanuary2,2012.

Correspondingauthor:,DepartmentsofMedicine,

BiochemistryandMolecularBiology,andCardiacSciences,JuliaMcFarlane

DiabetesRearchCentre,UniversityofCalgary,2998-3330HospitalDrive

NW,Calgary,AlbertaT2N4N1,.:ϩ1-403-220-2261;fax:ϩ1-

403-210-8113.

E-mail:dcwlau@

Seepage331fordisclosureinformation.

CanadianJournalofCardiology28(2012)326–333

0828-282X/$–efrontmatter©htsrerved.

doi:10.1016/.2012.01.001

coronaryartery,denof

hypertensionattributabletoobesityisveryhigh,andhasbeen

estimatedtobeapproximately80%formenandapproximately

60%forwomen.7Theoddsratioforhypertensionis1.7for

overweightcomparedwithnormalweightindividuals,2.6for

class1obesity(BMI30-34.9),3.7forclass2obesity(BMI

35-39.9),and4.8forclass3obesity(BMIϾ40).8

Thisreviewfocusontherelationshipofobesityandhy-

pertensioninadultsandchildren,themechanismslinkingobe-

sitytohypertension,whyweightlossisacornerstonetreatment

forobesity-relatedhypertension,andapproachestotacklethe

globalepidemicofobesity.

TheGlobalEpidemicandBurdenofObesity

Globallytheprevalenceofobesityhasbeensteadilyincreas-

omover9million

adultsin199countrieshaveindicatedthattheBMIincread

by0.4-0.5perdecadeworldwidebetween1980and2008.9

Thedramaticriinobesityratesgloballyisfueledbythein-

creadavailabilityofenergy-dendiets,increasinglyden-

taryphysicalactivitybehavioursand,importantly,massurban-

portionoftheworld’s

populationlivinginurbanareaclipdthe50%markin

2008,withtheurbanpopulationpredictedtoincreato4.9

billionby2030,whiletheruralpopulationixpectedtocon-

tractby28million.10Obesityisaconquenceoftheobeso-

genicenvironmentsthathaveevolvedinbothhighandlow

zationisincreasinglyviewedasapo-

tentialhealthhazardforvulnerablepopulations,namelythe

urbanpoorfrombothhighandlowincomecountries.

TheUSleadsthedevelopedworldwiththehighestobesity

rates,withaprevalenceof34%inadultsand17%among

children2-19yearsofage.11Projectionsbadonthecurrent

obesitytrendspredictthattherewillbe65millionmoreobe

adultsintheUSby2030.12InCanada,the2007-2009cohort

fromtheCanadianHealthMeasuresSurveyhada2.0increa

inmeanBMIwhencomparedwiththe1981data.13Twenty-

fivepercentofCanadianadultsand8.6%ofchildrenand

youthaged6-17wereobe.14ThemeanBMIofadultCana-

nthe

measureddata,theprevalenceofoverweightandobesityin

2008wasanalarming62%.14Nineteenpercentofmenand

21%ofwomenbetweentheagesof20to39wereclassifiedas

obe,whileforages60to69years,theprevalenceincreadto

34%and33%respectively.15Inadolescentsaged15to19

years,25%ofgirlsand31%ofboyswerealreadyoverweightor

obe.16Iftheobesitytrendcontinuesatthecurrentrate,half

oftheCanadianpopulationovertheageof40yearswillbe

classifiedasobewithin25years.15Sadly,theprevalenceof

obesityissignificantlyhigheramongaboriginalpeoplesinboth

adultsandchildren.14

Theincreasingprevalenceofoverweightandobesityinchil-

drenandyouthisparticularlydisturbingaschildhoodobesity

ispredictiveofadultobesity.1,17Whativenmorealarming

istheobrvationthatclusteringofCVDriskfactorsis

alreadyprentinoverweightchildren,leadingtoanin-

creadfutureriskofCVDinadults.18,19Whenthefig-

uresareappliedtoacomputer-simulationmodelofcoro-

naryarterydia(CAD)topredictexcessincidenceand

prevalenceofCADfrom2020to2035,theprevalenceof

CADwillincreabyarangeof5%to16%by2035,and

morethan100,000excesscasofCADwillbedirectly

attributabletochildhoodobesity.13Furthermore,arecent

studyinalargecohortof276,835Danishschoolchildren

foundthattheCVDrisksduringadulthoodincreadlinearly

withincreasingBMIateachagefrom7to13years.19Another

prospectivestudyin37,674apparentlyhealthyyoungmen,

whichtrackedBMIfromadolescencetoadulthoodwitha

meanfollow-upof17years,indicatedthatanelevatedBMIat

age17years—onethatisinthehighnormalrange—wasasso-

ciatedwithsubstantiallyhigherriskofCADinadulthoodat

age30years.20Thehazardratiofortheassociationofadoles-

centBMIwithCAD,aftermultivariateanalysisadjustedfor

age,familyhistory,BP,lifestylefactors,fastinggluco,and

triglyceridelevels,was6.85.20Availableevidencehasledmany

expertstopredictthatthecurrentgenerationofoverweightand

obechildrenmayhaveashorterlifespanthantheirpar-

ents.18,21Fortunatelyarecentstudyof6,328subjectswitha

meanfollow-upof23years,reportedthatifchildhoodobesity

isreducedortreated,theincreadCVDriskinadulthood

risksamongpeoplewhowere

overweightorobeaschildrenbutarenolongerobeas

adultsweresimilartotheCVDrisksinthopeoplewhowere

neverobe.22Thisstudysuggeststhatchildhoodobesity,if

successfullytreated,doesnotnecessarilyincreatheCVDrisk

permanentlyduringadulthood.

Obesityincreastheriskofmanychronicdias,notably

type2diabetes,hypertension,heartdia,stroke,musculo-

skeletaldias,teand

chronicdiasassociatedwithexcessadipositynotonlyneg-

ativelyaffectthehealth-relatedqualityoflifeofanindividual,

butalsothesubstantiallyhighercostsfromhealthcareandlost

matic

reviewdemonstratedthatobesityaccountsfor0.7%-2.8%of

directhealthcareexpenditureinmanydevelopedcountriesbut

couldbeashighas7%intheUS.23DatafromtheUSindicate

thatobepeopleincurmorefrequentphysicianvisits,higher

in-andout-patientcosts,andgreaterprescriptiondrugu.12

-

tionofobesityisnolongeraloftybutrathernecessarygoalthat

urgentlycallsforactionfromgovernmentsatalllevels,inconjunction

withallpublicandprivatectorstakeholders,inordertocombata

riousandgrowingpublichealthconcern.

poidscorporeletdesanté.Laprienchargeréussiedesper-

sonnespréobètobèsrequiertuncadremultifacette,détaillé

etcomplet,quiintègrelesmodèlesdesantédelapopulation,de

santépubliqueetdesantémédicalepouréliminerlesfacteurs

proximauxetdistauxdel’environnementobésogènedanslequel

éventiondel’obésitén’estplusunbutnoble,mais

plutôtunbutnécessairequiexigedemanièreurgentel’intervention

detouslesordresdegouvernement,conjointementavectoutesles

partiesprenantesdescteurspublicetprivé,pourcombattrece

sérieuxetcroissantproblèmedesantépublique.

NguyenandLau

ObesityandHypertension

327

InCanada,thetotaldirecthealthcarecostsattributableto

obesityhaveescalatedfromCAD$1.8billion(2.4%ofthetotal

healthexpenditures)in1997toCAD$4.6billionin2006

(4.1%ofthetotalhealthcareexpenditures).24,25Inadditionto

medicalcosts,theindirectcostsfromobesityasaresultof

decreadyearsofworkinglife,disability-freelife,andwork

abnteeismvsprenteeismaredifficulttoquantifybutcould

bequitesignifiogetherthedataindicatethat

obesityexactsahugehealthandeconomicburdenfromboth

individualsandthesociety.

CausalLinkBetweenObesityandHypertension

Hypertensionisthemostcommoncardiovascularriskfac-

torpredisposingtoCAD,stroke,andstructuralendorgan

damage.2Thelinkbetweenobesityandhypertensionhasbeen

documentedinmanylargepopulationandepidemiological

studiesinadultsandtheburdenofhypertensionattributableto

obesityisveryhighinbothmenandwomen.7,8Population-

badstudiesconsistentlydemonstrateanincreadriskinthe

developmentofhypertensionamongoverweightandobe

edwithnormalweightcohorts,obeindivid-

ualshavea2-to3-foldriskfordevelopinghighBP.26The

meansystolicBP(SBP)anddiastolicBP(DBP)valueswere

estimatedtobe9and7mmHghigherinobemenand11

and6mmHghigherinobewomenrelativetoacohortwith

normalBMI.27

Theobrvationsthatoverweightandobechildrenwith

elevatedBPmayalreadyhavestructuralarterialabnormalities,

suchasincreadcarotidintimal-medialthicknessandleftven-

tricularmass,suggestsacausalrelationshipbetweenobesity

andhypertension.19,21Obeadolescentshaveelevated24-

hourambulatoryBPreadingscomparedwiththeirnonobe

cohorts,withexcessvaluesashighasϩ19.3mmHgsystolic

andϩ10.1mmHgdiastolicin1study.28Notsurprisingly,the

riskofdevelopinghypertensionincreaswithbodyweight.A

Canadiancohortdemonstrateda7-foldlikelihoodofdevelop-

inghypertensioninobechildren.29Itisnotknownwhether

weightlossortreatmentofhypertensionwillcompletelyre-

verthestructuralarterialchangesthathaveoccurredinover-

y-relatedhypertensionis

increasinglyrecognizedbysomeexpertsasadistinctphenotype

thatrequiresamorevigilantapproachtodiagnosis,treatment,

andprevention.

Thehallmarkofobesityistheprenceofexcessivebodyfat,

whichistheconquenceofeitheroverconsumptionoffood,

decreadphysicalactivity,etissueiscompod

ofmatureadipocytes,preadipocytes,endothelialcells,and

macrophages,andisnolongermerelyviewedasapassivere-

adipocytesareactiveendo-

crineandparacrinecellscretinganever-increasingnumberof

mediatorsthatparticipateindivermetabolicprocess.30,31

Thebest-knownadipotissue-derivedhormoneisleptin,

whichfunctionsasafeedbackregulatortosuppressappetite

centrallyinthehypothalamus.31Circulatingleptinlevelsare

correlatedtoadiposityandareelevatedinobepeople.31It

turnsoutthatmanyoverweightandobepeopledevelopcen-

tralleptinresistanceandtheirappetitesarenotsuppresdde-

hasbeenlinkedto

hypertensionandthisassociationwasfirstreportedinanimal

andmorerecentlyinhumanstudies.32-34Severalmechanisms

,

leptinaltersrenalsodiumbyupregulatingrenalNa,K-ATPa

activity.32Second,leptinalsoactivatestherenin-angiotensin-

aldosteroneaxisaswellasthesympatheticnervoussystem,

bothofwhichcouldleadtothedevelopmentofhyperten-

sion.32Third,higherleptinlevelsmayberelatedtoinsulin

resistancewhichisalsoassociatedwithhypertension.33,34Fi-

nally,leptincouldactinconcertwithotherproinflammatory

cytokinestoinducevascularoxidativestressandarterialhyper-

tension.34

Excessadipotissueinoverweightandobepeople,espe-

ciallyfromthevisceraldepot,becomesdysfunctional,andis

characterizedbyapreponderanceofhypertrophiedadipocytes

withinfihangesleadtoexces-

sivereleaofcytokinesandproinflammatorymediatorsfrom

adipotissue,tionto

leptin,interleukin-6,tumournecrosisfactor-␣,plasminogen

activatorinhibitor-1,andC-reactiveproteinareamongthe

proinflammatoryakipokinesthatareupregulatedinadipo

tissueandcontributetothesystemicinflammatorystateand

theincreadvascularoxidativestressobrvedinobesity.30

Adiponectin,aproteinabundantlyproducedbyadipotissue,

isanimportantstimulantofnitricoxidesynthaactivityand

confersprotectionagainstoxidativestressandinsulinresis-

atinglevelsofadiponectinaredecreadinobesity

partlybecauitsproductionissuppresdbytheproinflam-

ogether,theunoppodupregula-

tionofproinflammatoryadipokinesandthesuppressionof

adiponectinwreakhavoconglucoandlipidmetabolism,re-

sultinginvascularendothelialdysfunction,andtheprogression

ofatheroscleroticchangeswithintheveslwall.30,31The

metabolicabnormalitiesnotonlyexaggeratetherisksforCVD

butalsoinsulinresistanceandtype2diabetes,andhaveledto

thedevelopmentofthemetabolicsyndromeconcept,30,35

morebroadlyreferredtoascardiometabolicrisk.36

Acommonfeatureofhypertensionistheactivationofthe

studiessuggestthat

adipotissueisasourceofangiotensinogen,angiotensin-con-

vertingenzyme,andrenin,whereitscontributiontothecircu-

latinglevelsofthecomponentsoftherenin-angiotensin-al-

dosteroneaxisbecomesanimportantconsiderationinthe

prenceofobesity.37Thefindingofadipocytehypertrophy,

lowbodyweightandlowBPinangiotensinknock-outmice

lendssupporttoamoredirectroleofadipotissueinthe

pathogenesisofhypertension.37

Itshouldbenotedthathyperinsulinemiaandinsulinresis-

tanceinobesitycanalsoinducehypertensionviaothermech-

anisms,includingchronicstimulationofsympatheticandvas-

culartonealongwithantinatriureticeffects.30,37

Thereareothermechanismswherebyobesitycouldcontrib-

mple,sleep

apnea,acommoncomplicationofobesity,couldalterthehy-

pothalamic-pituitary-adrenalaxisbyinducinghighercortisol

levels,aswellasactivatingthesympatheticnervoussystem.

HealthBehaviourManagementofObesity-

RelatedHypertensioninAdults

Thecornerstonetreatmentofobesity-relatedhypertension

isweightlossthroughhealthbehaviouralchangesandreduced

lossdiminishesboththe

328CanadianJournalofCardiology

Volume282012

augmentedrenin-angiotensin-aldosteroneaxisactivityandthe

ionin

bodyfat,especiallyfromthevisceraldepot,improvesinsulin

eralprinciple

ofweightlossistheachievementofanetnegativeenergybal-

nbeaccomplishedbyhealthbehaviourmodifica-

tionalone,orwithadjunctivepharmacotherapy,andinsome

lectedcas,onofahealthierlifestyle

isntialforthelong-termsuccessinachievinglowerBP

cludesappropriateweightlosstoachievetarget

healthgoals,maintenanceofweightloss,andpreventionof

weightregain,regularphysicalactivity,reduceddietarysodium

intake,moderationofalcoholconsumption,smokingcessa-

tion,essaryhealthbehaviour

modificationscanbestbedeliveredbyaninterdisciplinary

healthcarethatincludesdietaryandexercicounlling,social

support,andpossiblycognitivebehaviouraltherapy.

TheefficacyofhealthbehaviourmodificationonBPin

overweightpatientsispartlydependentonthemagnitudeof

aofaslittleas2kgcanreduceSBPby4

mmHgandDBPby3mmHg.38Ameta-analysisof25ran-

domizedtrialsconcludedthataweightlossof5.1kgachieved

byenergyrestriction,increadphysicalactivity,orboth,can

lowerSBPby4.4mmHgandDBPby3.6mmHg(e

Table1).Eachkgweightlossisassociatedwithareductionof

1mmHginSBPofand0.92mmHginDBP.39Weightloss

exceeding5kgisassociatedwithmoresignificantBPlowering,

uptoa6.6mmHgreductioninSBPand5.1mmHgreduc-

tioninDBP.40ThisBPloweringeffectbecomesmoredramatic

inpatientswithclassII(BMI35–39.9)orclassIII(BMIϾ40)

subt,reductionof15mmHgSBPand6mm

HgDBPwaspossibleifa10kgweightlossachievedthrough

dietandphysicalactivityinterventionwasmaintainedfor1

year.39

AerobicexercialsolowersBPinbothhypertensiveand

-analysisof54randomized

controlledtrialsconcludedthataerobicexerciwasassoci-

atedwithareductioninbothSBPandDBP,3.8mmHg

and2.6mmHg,respectively.41Theaverageintervention-

relatedweightlosswas0.4kg,whichwasnotstatisticallyor

clinicallysignifir,thispointstothemecha-

nismwherebyexercilowersBPindependentofweight

loss,potentiallythroughimprovementsininsulinresistance

andhyperinsulinemia.

DietarypatternsalsoappeartoexertbeneficialeffectsonBP

tstudiedistheDietaryApproachestoStop

Hypertension(DASH)ingan8-weekdietrichin

fruitsandvegetables,andlow-fatdairyproducts,withreduced

saturatedandtotalfat,theSBPandDBPwerereducedby11.4

mmHgand5.5mmHgrespectivelyinpeoplewithhyperten-

sionwhencomparedwiththecontroldiet.42WhentheDASH

dietwasadministeredwithdietarysodiumrestrictedfrom3.5

g/dto1.2g/d,therewasafurtherreductioninSBP7.1mmHg

inpeoplewithouthypertensionand11.5mmHginpeople

withhypertension.43Sodiumrestrictionisparticularlyrelevant

andeffectiveinoverweightandobepeople,astheyhavea

greaterpropensityforsodiumretentionasadirectconquence

oftheabnormalmetabolicchangesdescribedearlier.

ArecentUSstudysuggestedthatreducingdietarysaltby3

g/dcouldreducetheannualnumberofnewcasofCADby

60,000to120,000,strokeby32,000to66,000,andmyocar-

dialinfarctionby54,000to99,000,inconjunctionwithan

annualreductionindeathsfromanycauby44,000to

92,000.44Theauthorsconcludedthatmodestreductionsin

dietarysaltcouldsubstantiallyreducecardiovascularevents,

resultinginanestimatedsavingsofUSD$10billionto

USD$24billioninhealthcarecosts,andshouldthereforebe

recommendedasapublichealthtarget.

PharmacotherapyforObesity

Pharmacotherapyforobesityisconsideredasanadjunct

whenhealthbehaviouralchangesfailtoachievethegoal

targetsinBPand/orothermetaboliccomorbidities.1Cur-

rently,orlistatistheonlydrugapprovedasalong-term

atisagastrointestinallipa

inhibitorthatreducesdietaryfatabsorptionandfatcalorie

intakebyapproximately30%.45Axpected,thecommon

sideeffectsincludebloating,fecalincontinence,andab-

4years,orlistatcanmaintainaneg-

ativeweightchangeofabout6kgandareductionofSBP

r,the

additionalbenefitoforlistatontopofhealthmodification

alonewasminimal,onlyachievinganadditional1.5mmHg

SBPand0.7mmHgDBPreduction.46Overall,arecent

meta-analysisof4orlistattrialsconcludedanetBPbenefit

ofϪ2.5mmHgSBPandϪ1.9mmHgDBP.47

Severalantiobesitydrugsarecurrentlyinpha3clinical

tisshowingpromiisliraglutide,aglucagon-

likepeptide-1analoguecurrentlyapprovedasanantihypergly-

cemicagentinmostcountries,whichrevealedgreaterweight

loss(Ϫ5.5toϪ7.2kg)comparedwithorlistat(Ϫ4.1kg).48

LiraglutidealsoreducedBPmodestly(Ϫ5.6toϪ6.9mmHg

SBPandϪ1.2toϪ2.9mmHgDBP).Datafromalargepha

IIItrialinvolvingacombinationofphentermineandtopira-

matedemonstrateda10kgweightloss,alongwithaBPreduc-

tionof5.6mmHgSBPand3.8mmHgDBPat56weeks.49

BariatricSurgery

Atprentbariatricsurgeryisconsideredforindividuals

withclassIIIobesity(BMIϾ40)orclassIIobesity(BMIϾ

35)withcomorbidconditionssuchashypertensionandtype2

diabetes.1Bariatricsurgeryprocedurescanbeclassifiedasre-

strictive,malabsorptive,orcombinationofbothrestrictiveand

pesofbariatricproceduresarenow

availableinCanada.

Firstly,adjustablegastricbandingisarestrictiveprocedure

thatinvolvestheplacementofanadjustablesiliconeband

edBPrespontoobesityintervention

Intervention

SBP/DBP(mmHg)

AdultsAdolescents

HealthbehaviourmodificationsϪ6.6/Ϫ5.1Ϫ7/Ϫ2

AerobicexercionlyϪ3.8/Ϫ2.6Nodata

DASH-sodiumrestrictionϪ11.4/Ϫ5.5Nodata

OrlistatϪ2.5/Ϫ1.9ϩ1.1(NS)/Ϫ0.51

Adjustablegastricbandingϩ2.1/Ϫ1.4(NS)Ϫ12.5/Ϫ6.0

Roux-en-YgastricbypassϪ4.7/ϩ10.4(NS)Insufficientdata

BP,bloodpressure;DASH,DietaryApproachestoStopHypertension;

DBP,diastolicBP;NS,statisticallynonsignificantdifferencefromcontrol

group;SBP,systolicBP.

NguyenandLau

ObesityandHypertension

329

aroundtheupperportionofthestomachtoreduceitsoverall

oluteweightlossisaboutby27kgor47%of

excessweight50butitffectonhypertensionhasbeendisap-

pointing,withminimalimprovementinsubjectsfollowedpro-

spectivelyforupto10years.51

Secondly,gastricbypass,orRoux-en-Y,isthegoldstandard

procedure,wherebythesizeofthestomachisreducedtocreate

asmallerpouchthatisconnectedtoasmallgmentofthe

soluteweightlossofgastricbypass

surgeryis43kgandthemeanexcessweightlossis62%.50

Usingretrospectiveobrvationaldata,gastricbypasssurgeries

appeartoimproveorresolvehypertensionintherangeof30%

to70%after1to5years.50,52-55TheSwedishObeSubjects

(SOS)studyisthelargestandlongestprospectivetrialofbari-

atricsurgerytodateandincludedaportionofgastricbypass

10years,therewasanonsignificanteffectonBPin

thissubgroupdespiteasignificantweightloss.51

Thirdly,verticalsleevegastrectomyisarelativelynewre-

strictiveprocedure:thestomachisstapledvertically,thereby

removingabout85%ea

stand-aloneprocedure,orasafirststepforthegastricbypass

ianregistryof34patients

showedameanweightlossof27.4kganda53%resolutionof

hypertensionatameanfollow-upof10months.56Thefind-

ingsareconsistentwithotherreportsonlaparoscopicsleeve

gastrectomy,whichdemonstrateda40%-60%rateofhyper-

tensionresolutionintheshort-term.57,58Theabove3bariatric

proceduresaremainlyperformedlaparoscopically;con-

quently,peri-andpostoperativecomplicationsarereduced

drastically.

Fourthly,themosttechnicallychallengingprocedureisbil-

algastrec-

tomyisperformedtocreateasleeve-shapedstomach,andthe

smallbowelisdividedinto2limbs—theentericlimbcarrying

food,andthebiliopancreaticlimbcarryingbileandpancreatic

juice,andanultra-shortcommonchannelafteranastomosisof

ocedureresultsinthegreatestweightloss

(64%ofexcessweight)alongwithresolutionofdiabetes(ap-

proximately95%)unately,a

recentprospectivecomparisonfoundnoadvantageofthispro-

cedureovertheRoux-en-Yinthetreatmentofhypertension.59

Regardlessofthesurgicalprocedureamultidisciplinaryweight

managementteamisrequiredforasssment,lectionof

propercandidates,pre-andlong-termpostoperativefollow-up

andmanagement.

ManagementofObesity-RelatedHypertensionin

OverweightandObeAdolescents

Healthbehaviourmodificationremainsthecornerstonefor

thetreatmentofoverweightandobeadolescentswithhyper-

r,no

consistentprotocolsareavailableonsuchinterventionsandfew

1-yeartrainingprogramofphysicalactivity,nutrition,andbe-

haviourtherapy,SBPandDBPwereloweredby7and2mm

Hgrespectively.60AshortertermstudyreportedgreaterBP

reductionby14and9mmHg(SBPandDBP)afteronly20

weeksoflifestyletraining.61

Theefficacyandsafetyandofpharmacotherapyandsurgi-

calinterventionsforobesitytreatmentinchildrenislimited.

Tworandomizedcontrolledtrialsinvolvingorlistathavebeen

studiedinthepediatricpopulation,withonly1reportingBP

changes.62,63Inthe54-weektrialorlistatwassuperiortohealth

behaviourmodificationsalonewithrespecttoweightloss,re-

erenceinSBPwas

noted,whileDBPwasreducedbyamere0.5mmHg.

Forthemassivelyobeadolescent,bariatricsurgeryis

scopicadjustablegastricband-

ingandtheRoux-en-Yprocedurearethe2proceduresper-

formedtodateandmostofthepublisheddataconsistofsmall

obrvationalandnotrandomizedstudies,withfollow-upin

lstudiesreportedimprovement

ectiverandomized

laparoscopicadjustablegastricbandingtrialin50adolescents

withBMIϾ35reportedameanweightlossof34.6kgafter2

saccompaniedbyareductioninSBPof12.5mm

HgandDBPof6.0mmHgwhencomparedwithbaline,but

wasstatisticallynonsignificantwhencomparedwiththecon-

trolgroup.64LimiteddataexistsforRoux-en-Ygastricbypass

surgery,whichisrervedforadolescentswithvereobesity

(BMIՆ50).However,significantimprovementsinhyperten-

sionarereportedwithsubstantialweightlosswithin1yearof

obrvation.65,66

PropodApproachestoTackletheObesity

EpidemicandItsImpactonHypertension

Theglobalpandemicofobesitycanonlybeeffectivelyre-

verdbydismantlingtheprincipaldeterminantsoftheobeso-

yisariouspublichealthconcern

andisaconquenceofpeoplerespondingnormallytothe

obesogenicenvironmentwheremoreprocesd,energy-den,

affordable,andeffectivelymarketedfoodareinabundantsup-

ply,inassociationwithincreasinglydentaryphysicalactivity

behaviourspromotedbythebuiltenvironmentandurbaniza-

ablythecontinuingtrendsofoverconsumptionof

foodanddecreadphysicalactivityleveloverthepastveral

decadesaretheproximalcausoftheunrelentingincreain

r,

thesocioculturalandsocioeconomicmilieuswithineachcoun-

tryorlocalcommunitycanmoderatetheenvironmental

driversandtosomedegreehelprevertheproximalcausof

obesity.

Successfulapproachestotacklingtheobesityepidemicwill

requireacomprehensive,multifacetedframeworkthatinte-

gratespopulationhealth,publichealth,andpersonalhealth

entionsaimedatreversingthe

-

ever,inordertoachievethe,governmentsatalllevelsmustbe

persuadedtoenactpoliciesthatfacilitatethecooperationof

consumers,publicandprivatectors,nongovernmentalorga-

nizations,andvariousindustries(food,rvice,transportation,

andbuilding,etc)inthepromotionofhigherlevelsofphysical

activityandtheconsumptionofhealthyfoodchoicesinaman-

-ledinterven-

tionsaremorelikelytochangethepopulationenvironments

systematicallyandthepopulation-wideeffectsaremorelikely

hexampleisa

compelling

evidencethathighsodiumintakecontributestothedevelop-

mentofhypertensionandthatreducingdietaryintakeby3g/d

330CanadianJournalofCardiology

Volume282012

couldgreatlydecreanewcasofheartdiaandstroke,and

deathsfromCVD,inacost-effectiveandpotentiallycost-sav-

ingmanner.44

Theworkplaceandschoolsarewherehealthybehaviours

canbepromotedandfosteredtooptimizehealthandreduce

llrequireleadershipand

cooperationfromboththepublicandcorporatectors.

Incentivesfromgovernmentsatthemunicipal,provincial

andterritorial,and/orfederallevelscouldgoalongwayto

ierem-

ployeesandchildrenwillbenefitsocietybyincreasingpro-

ductivityandprosperitywhileatthesametimereducingthe

healthcareburden.

Whileawaitingthedevelopmentofasystemsapproachto

tackletheobesityepidemic,healthcareprofessionalsfromalldis-

ciplinescontinuetoplayimportantrolesinthepreventionand

-

motingweightlossandweightmaintenancethroughhealthybe-

haviourmodificationwillremainanintegralcomponentofour

clinicalpractice,butweneedmoreeffectiveandsustainableinter-

ventionsaswellasanefficienthealthcareanddeliverysystemthat

facilitatesandevaluatesprogressinreductionofbodyweightand

obesity.

Theevidence-informedCanadianclinicalpracticeguide-

linesonthemanagementandpreventionofobesityprovided

recommendationsaimednotonlyatprimarycarepractitioners

butalsopublichealthandpolicymakersinthehopeofinte-

gratingpopulationhealth,publichealth,andmedicalap-

proachestotacklethegrowingproblemofobesity.1Manypro-

gramsandinitiativeshavebeenimplementedacrossthe

country,llycol-

laborativeinitiativessuchastheCanadianHarmonizationof

NationalGuidelinesEndeavour(C-CHANGE)whichisa

worthwhileattempttoharmonizealltheCanadianclinical

practiceguidelinesforthepreventionandtreatmentof

CVD,willrenewourcollectiveefforttowardsachieving

healthierbehavioursasadirectmeansofcurbingtheobesity

epidemicanddecreasingCVD.67Aglobalcampaign,enti-

tled“Healthyweight-healthybloodpressure,”wasinitiated

in2010bytheWorldHypertensionLeague,incollabora-

tionwithnationalandinternationalorganizations,toen-

hancepublicawarenessofobesityandhypertension.68The

,morethanever,

thereisanurgentneedtobringtogetherthepolicymakers

andallthestakeholderstoeffectsystemsandsocietal

changestoabolishtheobesogenicenvironment.

Disclosures

eivedrearchfunding,honoraria/

consultingfeesfromAlbertaInnovates-HealthSolutions,

CanadianDiabetesAssociation,CanadianInstitutesof

HealthRearch,Boehringer-Ingelheim,Bristol-Myers

Squibb,Dainippon,EliLilly,NovoNordisk,Pfizer,and

Sanofi;honoraria/consultingfeesfromAbbott,Allergan,

Amgen,Bayer,Merck,andNovartis;andpeer-reviewed

fundingfromAlbertaInnovates-HealthSolutions,Canadian

DiabetesAssociation,andCanadianInstitutesofHealthRe-

onflictsofinteresttodisclo.

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