The Causation, Consequences and Prevention of Obesity

A Public Health PerspectiveBy

Prof Winston G Mendes Davidson, CD; JP; MBBS; DTM&HHead, School of Public Health & Health Technology

University of Technology7.6.18

Presented at Annual Medical Conference Medical Association of Jamaica

TheScopeofObesity

1. It is estimated that over 1 billion persons worldwide are overweight, more than 300 million of whom are clinically obese.(WHO Obesity & Overweight: http://www.who.int/)

2. In the United States, >60% of adults are overweight or obese, and the number of obese children and adolescents is dramatically increasing(Wyatt SB, Winters KP, Dubbert PMAm J Med Sci. 2006 Apr; 331(4):166-74)

ThePandemic:GLOBALObesity

• Given its high and increasing prevalence, obesity is considered to be at pandemic levels.

• This has been attributed to an increasing worldwide adoption of energy-dense diets and sedentary lifestyles, probably as a consequence of urbanization and economic globalization

(WHO Obesity & Overweight: http://www.who.int/)

ObesityandFataccumulationdefinedbybodymassindexandwaistcircumferencealsoriskofobesityrelated

Co-morbidities.

WHATCAUSESOBESITY?

Whatdowemeanby“Cause”

• A cause is an event, condition, or characteristic without which the disease or condition would not have occurred.

• Risk factors are surrogates of underlying causes

• It is therefore important to distinguish between “risk factors” and “causes”

CaseStudy:UNDERSTANDING thePublicHealthPrincipleof “Causation”

• TheCasestudyofatrafficaccident– TheNarrativeoftheaccident

• Thefundamentalquestion– Whatcausedtheaccident?

Apply:TheEpidemiologicalTriad

HOST –(Driver)

ENVIRONMENT–

(TheROAD)

AGENT-(TheVehicle)

The3BIGCs:Context,Circumstances,Conditionsandre-emergingepidemics

Past:Epidemics

Present:Re-emergingEpidemic

“EPI-QUAD”: THE MODEL OF CAUSATION OF OBESITYCopyright: Prof Winston Davidson 2016

ENVIRONMENT HOST (MAN) AGENT (FOOD)

ENVIRON. INFLUENCES

1. Natural Environment:

Climate Change2. Human

Ecosystem: Society Economic, Social, Political, Cultural,

Religious Historical

PSYCHO-BIOLOGICAL

(Program response) Early environmental Influences, Genetics, Stress, Exposure to food

FOODAvailability, Production, Marketing/

GlobalisationEnergy intake vs Energy Out-

put

Multiple compounding variables working together. In Different: ContextsCircumstances Conditions

4.

1, 2, 3 & 4 DYNAMIC MULTIPLE VARIABLES WORKING TOGETHER giving rise to the OBESITY PHENOMENON reflecting different Contexts Circumstances & Conditions

1. 2. 3.

The“Web”ofCausationofObesityROOTCAUSE PROXIMATECAUSE

Hill's Criteria for Causality• Strength of the Association• Consistency• Specificity• Temporality• Biological gradient• Plausibility/Coherence• Experiment• Analogy

"Cigarettesmokingiscausallyrelatedtolungcancerinmen;themagnitudeoftheeffectofcigarettesmokingfaroutweighsallotherfactors."

• Adapted from: http://www.endotext.org/obesity/obesity22/obesityframe22.htm

ConsequencesofObesity

Obesity&Metabolicsyndrome

• TheMetabolicSyndrome:Isaclusterofmetabolicriskfactorscomingtogetherinasingleindividual

* GLUT4 is one of 13 sugar transporter proteins (GLUT1-GLUT12, and HMIT) encoded in the human genome (Joost and Thorens, 2001; Wood ...

Major metabolic risk factors resulting from obesity

1) Artherogenicdyslipidaemia2) Borderline-hightotalcholesterolconcentrations,3) Raisedtriacylglycerol(Triglyceride)

concentrations,4) SmallLDLparticles,andlowHDLconcentrations),5) Raisedbloodpressure,3)Insulinresistanceandglucoseintolerance,4)Abnormalitiesinthecoagulationsystem(procoagulantstate)

Question:DoestheMetabolicSyndromefullyexplaintheconsequencesofobesityanditscomorbiditiesonhumanhealth

andDisease?

• Answer:–TheMetabolicSyndromeasdefinedisnecessaryandessentialbutNOTsufficienttoexplainthefullpictureoftheconsequencesofObesityonhumanhealthanddisease

1.Obesity:ConsequencesPoorNutrition&LackofExercise(TheChildhoodObesityLifeCycle)

2.Obesity:ConsequencesObesityStressorsandMentalIllness

(PhysicalandbehaviouralillnessesincludingDepression)

Obesity&Depression• Feelings of sadness, anxiety or stress often lead people to

eat more than usual. Unless you act to address these emotions, however, these short-term coping strategies can lead to long-term problems.

• Although women are slightly more at risk for having an unhealthy BMI than men, they are much more vulnerable to the obesity-depression cycle. In one study, obesity in women was associated with a 37 percent increase in major depression.

• There is also a strong relationship between women with a high BMI and more frequent thoughts of suicide.

http://www.apa.org/helpcenter/obesity.aspx

Obesityandotherbehaviouraldisorders

• Binge eating, a behaviour associated with both obesity and other conditions such as anorexia nervosa, is also a symptom of depression.

• A study of obese people with binge eating problems found that 51 percent also had a history of major depression

http://www.apa.org/helpcenter/obesity.aspx

3.Obesity:ConsequencesSleepDeprivationanditsdysfunctionalsequelae

OBESITY&SLEEPDEPRIVATIONp Obstructive sleep apnea syndrome (OSAS) is

strongly associated with obesity and inflammation

p In obesity, effected production of most adipocytes impacts on multiple functions such as (Ghrelin & Leptin)n appetite and energy balance, n immunity, n insulin sensitivity, n angiogenesis, n blood pressure, n lipid metabolism and haemostasis, n all of which are linked with cardiovascular disease

Sleep duration and cardio-metabolic risk: a review of the epidemiologic evidence Kristen L. Knutson, Ph.D.

Obesity&Sleep• DrKnutsonaccumulatedevidencefromexperimentaland

observationalstudiesofsleep.• Observationalstudiesrevealedcross-sectionalassociations

betweengettingfewerthansixhourssleepandincreasedbodymassindex(BMI)orobesity.

• The studies revealed how signals from the brain which control appetite regulation are impacted by experimental sleep restriction.

• Inadequate sleep impacts secretion of the signal hormones ghrelin, which increases appetite, and leptin, which indicates when the body is satiated.

• This can lead to increased food intake without the compensating energy expenditure.

ObesityandSleepinChildren

• The evidence suggests the association between inadequate sleep and higher BMI is stronger in children and adolescents.

• It also shows that sleep deficiency in lower socioeconomic groups may result in greater associated obesity risks.

4.Obesity:ConsequencesTherelationshipbetweenObesity andthe

naturalandsocialenvironments.(Thedevelopmentofchronicdiseasesincluding

cancersandgeneticdisorders)

ObesityandAirPollution• A study of New York City children found that those whose motherswere exposed to higher levels of polycyclic aromatic hydrocarbons(PAHs) during pregnancy had a greater risk of obesity at 5 and 7 yearsof age (Rundle et al. 2012)

• Airpollution,alongwithobesity,isariskfactorfornon-alcoholicfattyliverdisease(Kelishadi andPoursafa,2011)

• Obesityappearstoworsenthecardiovascularhealtheffectsofairpollution(Weichenthal etal.2014)

• Whenairqualityimproves,lungfunctionalsoimproves.YetastudyfromSwitzerlandfindsthatthisonlyholdstrueifthosepeoplearenotoverweightorobese(Schikowski etal.2013)

From Epidemiology Matters, by Katherine M. Keyes and Sandro Galea. Oxford University Press, 2014 (pages 94-95)

THEPREVENTIONOFOBESITYTheFourstagestheoryofpreventionisalogicalepidemiologicalframeworkdesignedtoensure:Stg1 Astateofhealthandwellnessisbuilt(healthresilience)andHealthystatusmaintained(Pre-PrimaryPrevention)Stg2 Healthrisksaremitigatedandnewcasesareavoided,detectedearlyandtreatedpromptly(PrimaryPrevention)- DecreaseIncidenceStg3 Oldandnewcasesaretreatedandpreventedfrombecomingtemporarilyorpermanentlydisabled(Secondaryprevention- DecreaseprevalenceStg4 Avertchronicityandrehabilitatepartiallydisabledcases(Rehabilitation)- Avertfurtherchronicity

HowmaycasebycasepreventionofobesitybeachievedbyPractitioners?

*5Pillarsofwellnessascountermeasurestotheconsequencesofobesitymustbepracticedatallfourstagesofprevention:

1. GoodnutritionvsPoorNutrition2. Regularexercise(Jamaicamoves)vsLackofexercise3. AdoptmeasurestocopewithstressvsAccepting

consequencesoftheviciouscycleofstress,mentalandphysicalharm

4. EnsureRestfulSleepvsSleepdeprivation5. SafeandHarmoniousenvironment vsHarmful/Toxic

livingandworkingenvironments*ThesemeasuresarereferredtoasthefivePillarsofWellness/AHealthylifestylepractice(W.Davidson- 1999)

TheFourStagesTheoryforthePreventionofObesity:AdoptingEpidemiologicalPrinciplesofPrevention

PreventionHARMONIOUS ADAPTATION of MAN

within the ENVIRONMENT/(Healthy Lifestyle)

COMMUNITY

State of Health(Wellbeing)

Non-InstitutionalResponse Institutional

Response

COMMUNITY

Risk reduction /Early detection & diagnosisIncidence interventionmeasures

Treatment and Repair (Prevalence interventionMeasures)

Rehabinterventionmeasures

Rising Costs: Prof W. Davidson. 1999. (copyright)

PRE-PRIMARY PREVENTIONBuilding Health Resilience and Maintaintenance Wellness)

PRIMARY P REVENTION (Decrease Incidence)

SECONDARY PREVENTION(Decrease Prevalence)

TERTIARY PREVENTION(Avert Chronicity)

Rehab Response

PreventiveCountermeasurestotheDynamic“Web”ofCausationofObesityROOTCAUSE PROXIMATECAUSE