Azarpazhooh, Mahmoud R.

Hachinski, Vladimir

English

Scholarship@Western

Western UniversityScholarship@WesternAnatomy and Cell Biology Publications Anatomy and Cell Biology Department10-2018Air pollution: A silent common killer for stroke anddementiaMahmoud R. AzarpazhoohWestern UniversityVladimir HachinskiWestern UniversityFollow this and additional works at: https://ir.lib.uwo.ca/anatomypubPart of the Anatomy Commons, and the Cell and Developmental Biology CommonsCitation of this paper:Azarpazhooh, Mahmoud R. and Hachinski, Vladimir, "Air pollution: A silent common killer for stroke and dementia" (2018).Anatomy and Cell Biology Publications. 154.https://ir.lib.uwo.ca/anatomypub/154EditorialAir pollution: A silent commonkiller for stroke and dementiaFindings from the Global Burden of Disease (GBD)study showed that between 1990 and 2015, neurologicaldisorders were the second largest cause of death(behind cardiovascular diseases) and the largest globalcause of disability-adjusted life-years life-years(DALYs) worldwide.1 Not surprisingly, dementia, asthe third most prevalent neurological disorder andstroke with the largest proportion of total DALYsand deaths among all neurological disorders, plays akey role in such huge worldwide health burden.1Therefore, widespread prevention measures of strokeand dementia are becoming an inevitable necessity tofight against the health/economic burden of thesepotentially preventable disorders. The good news isthat more than 90% of the stroke burden is attributableto modifiable risk factors, including behavioral (e.g.smoking), metabolic (e.g. diabetes mellitus), and envir-onmental factors (e.g. air pollution).2 What missing inthe current reports of GBD studies are data on theextent to which stroke and dementia pose risks foreach other3 and consequently to what extend preven-tion of one or both simultaneously can decrease theburden of neurological disorders in total. Ideally, anypreventive measure should be focused more on shareand preventable risk factors and should be started atearliest stage of disease, i.e. ‘‘brain-at-risk stage’’ whenthe risk factors are present in clinically asymptomaticindividuals.4,5 In fact, stroke and dementia are one ofthe best examples in this ideal preventive model as theyshare many preventable behavioral and metabolic vas-cular risk factors.6 However, the current literature hasremained largely silent about commonalities betweenenvironmental risk factors of stroke and dementia,such as air pollution.Now, in a thorough review, Yannick Béjot and col-leagues show that air pollution is a common risk factorfor both stroke and dementia. What striking in thisstudy is the magnitude of air pollution impact: aboutone third of the global stroke burden and about onefifth of the global dementia burden can be attributed toair pollution, especially small particulate matter(<10 mm in diameter (PM10) and <2.5mm in diameter(PM2.5)) and ozone. Béjot et al. also provide educa-tional materials for readers explaining how with direct(e.g. inflammation) and indirect cardio-neuro-vascularmechanisms, air pollution may lead/enhance underly-ing pathophysiological changes of cerebrovasculardisorders and neurodegeneration. In this study, theauthors also identify those at risk of air pollution,including children and the elderly, those with other vas-cular risk factors, history of stroke, and individualsliving in less privileged areas. These are important find-ings emphasizing a targeted individual centered publichealthcare plan to decrease the burden of stroke anddementia in those at a higher risk. The authors alsorecommend wisely for future research to identify, forexample, the impact of different types of air pollutionand life-time cumulative effects of pollutants on stroke/its subtypes and dementia. Perhaps, the following stu-dies/expert national and international meetings shouldfocus on short- and long-term action plans to controlhealth impact of air pollution as a major global threat.These studies should provide adequate information forpublic as well as policy makers at international (such asG20 members) and national levels. Currently, despite arapid decline in transportation emissions in the UnitedStates and Europe, a troubling trend is that the use ofvolatile chemical products including pesticides, coating,printing inks, adhesives, cleaning agents, and personalcare products now account for half of fossil fuel volatileorganic compound emissions in industrialized cities.7Therefore, any national/international plan shouldinclude a range of activities from in-home fuels selec-tions to emission standards. Even at the time of newnational law legislations, it is vital to consider the pos-sible indoor/outdoor impact of the law on air quality.For example, is it possible that with a trend towardmarijuana legalization in many countries, we canendanger indoor air quality, in particular for childrenand the elderly who are often more vulnerable to airpollution?In summary, Yannick Béjot and colleagues providepersuasive evidence about the impact of air pollutionon stroke and dementia.8 This is a thorough and atimely review with adequate educational material forreaders and informative data for health policy makers.References1. GBD 2015 Neurological Disorders Collaborator Group.Global, regional, and national burden of neurological dis-orders during 1990–2015: a systematic analysis for theGlobal Burden of Disease Study 2015. Lancet Neurol2017; 16: 877–897.International Journal of Stroke, 13(7)International Journal of Stroke2018, Vol. 13(7) 667–668! 2018 World Stroke OrganizationArticle reuse guidelines:sagepub.com/journals-permissionsDOI: 10.1177/1747493018784476journals.sagepub.com/home/wso2. Feigin VL, Roth GA, Naghavi M, et al. Global burden ofstroke and risk factors in 188 countries, during 1990-2013:a systematic analysis for the Global Burden of DiseaseStudy 2013. Lancet Neurol 2016; 15: 913–924.3. Azarpazhooh M, Avan A, Cipriano L, Munoz D, SposatoLA and Hachinski V. Concomitant vascular and neurode-generative pathologies double the risk of dementia. Inpress (accepted August 7, 2017). Alzheimer’s & Dementia2018; 14: 148–156.4. Bowler JV, Steenhuis R and Hachinski V. Conceptualbackground to vascular cognitive impairment. AlzheimerDis Assoc Disord 1999; 13(Suppl 3): S30–37.5. Hachinski V. Preventable senility: a call for action againstthe vascular dementias. Lancet 1992; 340: 645–648.6. Solomon A, Mangialasche F, Richard E, et al. Advancesin the prevention of Alzheimer’s disease and dementia.J Intern Med 2014; 275: 229–250.7. McDonald BC, de Gouw JA, Gilman JB, et al. Volatilechemical products emerging as largest petrochemicalsource of urban organic emissions. Science 2018; 359:760–764.8. Béjot Y, Reis J, Giroud M, Feigin V. A review of epide-miological research on stroke and dementia and exposureto air pollution. Int J Stroke 20108; Epub. doi: 10.1177/1747493018772800.Mahmoud Reza Azarpazhooh1,2,3 and Vladimir Hachinski1,21Department of Clinical Neurological Sciences, UniversityHospital, London Health Sciences Center, WesternUniversity, London, ON, Canada2Department of Epidemiology & Biostatistics, SchulichSchool of Medicine & Dentistry, Western University,London, ON, Canada3Department of Neurology, Ghaem Hospital, MashhadUniversity of Medical Sciences, Mashhad, IranCorresponding author: Vladimir Hachinski, Department ofClinical Neurological Sciences, University of WesternOntario, 339 Windermere Road, London, Ontario,Canada.Email: Vladimir.hachinski@lhsc.on.caInternational Journal of Stroke, 13(7)668 International Journal of Stroke 13(7)

Air pollution: A silent common killer for stroke and dementia

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Air pollution: A silent common killer for stroke and dementia

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