Epidemiology

of Malaria:

Population:Worldwide, itis estimatedthatabout198 million peopleare infectedwith malariaannually(Grady, 2015). About500,000 of theinfected personsdiewithin theyearof infection,butmostof thosewhodieare children.Approximately84 % of thedeathsare causedby severeswellingofthebrain.

Distribution:Distribution of a diseaserefersto thegeographicalareasthat a givendiseaseis prevalent.Thearticle“Brain swellingtiedto deathsfrom malaria”doesnot givea clearmapof thedistributionof malaria.However,thearticleemphasizesthatmostofthe malariacasesarereportedin Africa. Forexample,Grady (2015) statesthatabout half a million peopledieof malariaannually,butmostof them are childrenfrom Africa.

Determinants:Determinants are factorsthat influencethedistributionof a givendisease.Grady (2015) doesnot explainallsignificantfactorsthat contributetowards thedistributionof malariathat haveaffectedmanypeoplein Africa andotherpartsof theworld.However,Grady (2015) mentionsthatthespreadof malariaisfacilitatedby a parasitethat is distributedby mosquitoes. Therefore,mosquitoes are thekeyagentsof distributionof malaria.

Outcomes:Malaria infectionhas a widerangeof outcomesdepending on theseverityof infectionandthemedicalattentiongivento theinfected person.Cerebral malariacausesseverebraindamage,which in turnresultsin coma(Grady, 2015). Survivalsof malariacan becomeblind,deaf,oracquirelearningdisabilities.Malariacausesdeath,especiallyamong children(Grady, 2015).

Qualifications:All peoplecan sufferfrom malariairrespective of their ageorothersocialcharacteristics.Grady (2015) reportcasesof childandadult’sinfectionin differentpartsof theworld.Thismeansthatmalariacanaffectanypersonwhois within theenvironmentthat is conduciveforthemosquitoes to thrive.

Control:Control refersto measuresthat can be takento reducetherateof infectionorspreadof a givendisease.Grady (2015) statedthatthere is novaccine that can be usedto controlthespreadof malaria.However,there are somedrugsthat can be usedto reducethespreadof thisdiseaseto someextent.

Hillscriteria

Temporalrelationship:

Inthecigarettesmokingcasestudy,thesubjectsbegansmokingbefore sufferingfrom lung cancer(Snow, 2011).

Inthecaseof an associationbetween cancerandmagneticfield,there is noevidencethatthe magneticfieldprecedescancer(Kimball, 2011).

Strength:

Thecasestudyshowsthatpeoplewhosmokecigaretteare 10timeslikelyto sufferfrom lung cancerthan their non-smoking counterparts(Snow, 2011).

Astatisticalanalysisof thedata on theassociationbetween cancerandcloseness tothe magneticfieldat a 95 % confidencelevel didnot indicateanyrelativeriskat all(Kimball, 2011).

Dose-responserelationship:

Inthecaseof cigarettesmoking,theriskof sufferingfrom lung cancerincreaseswith thenumberof cigarettesthatone smokes(Snow, 2011).

Thereis noevidenceof riskof cancerbeyond theexposurelevel of 0.400-0.99 µt (Kimball, 2011).

Consistency:

Inthecasestudyreportedby Snow (2011), one studyfocusedon therelationshipbetween lung cancerandsmokingin a groupof physiciansfrom Britain, whiletheotherstudyassessedtheassociationin a groupof 187,783 American volunteers.Surprisingly, thetwo studiesidentifiedthattheriskof sufferingfrom lung cancerwaspositivelyassociatedwith thenumberof cigarettesthatone smokedper day.

Onestudyindicatedthatcloseness to powersincreasestheriskof cancerby 2-3 folds,buta secondstudydidnot indicateanyassociation(Kimball, 2011).

Plausibility:

Cigaretteshaveover 40 differentchemicalsthat are responsiblefortheoccurrenceof chemicals.Thishas beenprovenin a laboratoryusingtheratmodels(Snow, 2011).

InVitrostudiesfailedto identifythepossibilitythatmagneticfieldsresultin oncogenic changes(Kimball, 2011).

Considerationof alternateexplanations:

Proponentsof thetobaccoindustryhavearguedthatlaboratoryandepidemiological proofof associationbetween lung cancerandsmokingaredifferent(Snow, 2011).

Thereare noalternative explanationsregardingtheassociationbetween cancerandcloseness to powerlines.

Experiment:

Cigarettesmokingisrecognizedas thelargestsinglecauseof illnessthat can be preventedby avoidingsmoking(Snow, 2011).

Itisdifficultto developan experimentalregimen to alterorpreventtheoccurrenceof canceramong peoplelivingcloseto powerlines.

Specificity:

Cigarettesmokingcausesmultipleillnesses,butthelackof specificity is not sufficientto negatethecausal relationship.

Itisdifficultto statethatcloseness tothe powerlinecauseone typeof conditionsince there is noproveof theassociationbetween closeness tothe powerlineandcancer.

Coherence:

Itiswellunderstoodthatthe40 chemicalsfoundin tobaccohavethecapacityto causecancer,which supportstheargumentthatsmokingcauseslung cancer(Snow, 2011).

Theassociationbetween cancerandmagneticfieldisnot basedon anycurrentstateof understandingandknowledge.

Therefore,thelinkbetween lung cancerandsmokingis a causal relationshipwhilethelinkbetween nearnesstothe powerlineandcanceris a mereassociation.

References

Grady,D. (2015, March 18). Brain swelling tied to deaths from malaria. TheNew York Times.Retrieved March 26, 2015, fromhttp://www.nytimes.com/2015/03/19/health/some-malaria-deaths-in-children-linked-to-brain-swelling.html?_r=0

Kimball,W. (2011). Do magnetic fields cause cancer? KimballBiology Pages.Retrieved March 26, 2015, fromhttp://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/MagneticFields.html

Snow,J. (2011). . KimballBiology.Retrieved March 26, 2015, fromhttp://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/.html