HomeJournal of the American Heart AssociationAhead of PrintExcess Global Blood Pressure Associated With Fine Particulate Matter Air Pollution Levels Exceeding World Health Organization Guidelines Open AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citations ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toOpen AccessLetterPDF/EPUBExcess Global Blood Pressure Associated With Fine Particulate Matter Air Pollution Levels Exceeding World Health Organization Guidelines Robert D. Brook, Issam Motairek, Sanjay Rajagopalan and Sadeer Al‐Kindi Robert D. BrookRobert D. Brook *Correspondence to: Robert D. Brook, MD, Division of Cardiovascular Medicine, Department of Internal Medicine, Wayne State University, 400 Mack Avenue, Detroit, MI 48201. Email: E-mail Address: [email protected] https://orcid.org/0000-0002-8521-7262 , Division of Cardiovascular Diseases, Department of Internal Medicine, , Wayne State University, , Detroit, , MI, , USA, Search for more papers by this author , Issam MotairekIssam Motairek https://orcid.org/0000-0003-3294-8659 , Division of Cardiovascular Medicine, Department of Medicine, , Case Western Reserve University/University Hospitals Cleveland Medical Center, , Cleveland, , OH, , USA, Search for more papers by this author , Sanjay RajagopalanSanjay Rajagopalan https://orcid.org/0000-0001-6669-8163 , Division of Cardiovascular Medicine, Department of Medicine, , Case Western Reserve University/University Hospitals Cleveland Medical Center, , Cleveland, , OH, , USA, Search for more papers by this author and Sadeer Al‐KindiSadeer Al‐Kindi https://orcid.org/0000-0002-1122-7695 , Division of Cardiovascular Medicine, Department of Medicine, , Case Western Reserve University/University Hospitals Cleveland Medical Center, , Cleveland, , OH, , USA, Search for more papers by this author Originally published12 Apr 2023https://doi.org/10.1161/JAHA.122.029206Journal of the American Heart Association. 2023;0:e029206High blood pressure (BP) is the leading risk factor for global mortality.1 The current prevalence well exceeds 1 billion people and is expected to greatly increase over the ensuing years.1 Although there are many contributors to the rising hypertension pandemic, an underappreciated, yet important, factor may be fine particulate matter <2.5 μm (PM2.5) air pollution. PM2.5 also ranks among the top risk factors for global mortality, with over half of the health effects attributable to cardiovascular diseases.1 Most importantly, exposure to ambient PM2.5 has been convincingly shown to promote significant elevations in BP.2, 3 In this context, we sought to estimate association between global PM2.5 concentrations and worldwide excess BP levels.4The data that support the findings of this study are available from the corresponding author upon reasonable request. Population‐weighted annual PM2.5 exposures for 2019 (latest data) were abstracted from the Global Burden of Disease Collaborative Network, which uses satellite and ground‐level monitoring plus chemical transport models to provide concentrations at 0.1°×0.1° grids.5 The PM2.5 exposure‐to‐BP‐response relationship was based on the most recent meta‐analysis: increases of 0.63 and 0.31 mm Hg in systolic and diastolic BP levels, respectively, per 10 μg/m3 elevation in long‐term PM2.5 exposure.3 Population‐level excess BP was estimated as the magnitude of BP elevations related to PM2.5 concentrations above 5 μg/m3 (2021 World Health Organization Air Quality Guidelines).4 For example, [(country average PM2.5–5)×0.63/10] for excess systolic BP. Results were stratified by country, World Bank region, and sociodemographic index (SDI).5 Institutional review board approval was not required because the current analysis uses publicly available data.The mean global annual population‐weighted PM2.5 exposure was 42.6 μg/m3. The corresponding elevations in average worldwide systolic and diastolic BP levels were 2.4 and 1.2 mm Hg, respectively (Figure [A]). There were major differences in estimated excess BP levels by World Bank regions that were generally higher in locations with lower SDIs (Figure [B]). Countries with the highest excess BP levels (in millimeters of mercury) included India (4.9/2.4), Nepal (4.9/2.4), Niger (4.7/2.3), Qatar (4.5/2.2), and Nigeria (4.1/2.0). Given relatively low PM2.5 levels in the United States (7.7 μg/m3), the associated excess BP was small (0.2/0.1). The 2005 World Health Organization Air Quality Guidelines (annual PM2.5 of 10 μg/m3) showed slightly smaller excess BP globally (2.1/1.1), as well as for low SDI (2.9/1.4) and high SDI (0.2/0.1) countries.Download figureDownload PowerPointFigure Figure. . Geographic distribution of estimated excess BP associated with PM2.5 levels above the World Health Organization Air Quality Guidelines of 5 μg/m3 in 2019 (A) and world map showing excess systolic and diastolic BP (using the 2021 World Health Organization Air Quality Guidelines) in each country and by specific groupings (World Bank regions and SDI) (B).BP indicates blood pressure; DBP, diastolic blood pressure; PM2.5, fine particulate matter <2.5 μm; SBP, systolic blood pressure; and SDI, sociodemographic index.These data support a substantial global population‐level burden of BP elevations associated with ambient PM2.5. Although the magnitude of association varied geographically in relation to air quality, the overall global BP elevation averaged 2.4/1.2 mm Hg. Our broad estimations suggest that the contribution of PM2.5 to the hypertension pandemic is large, given the billions of people involuntarily exposed. Ninety‐nine percent of the global population faces PM2.5 levels above current World Health Organization Air Quality Guidelines.1 The results also indicate that specific countries (eg, India, Nigeria) and regions (eg, South Asia, Africa, lower SDI) suffer the greatest public health burdens due to higher excess BP levels associated with worse air quality combined with enormous populations at risk.We estimated BP responses to PM2.5 derived from a meta‐analysis of 24 studies involving wide‐ranging global pollution levels.3 However, our results likely represent conservative approximations. A meta‐analysis of randomized double‐blind air cleaner trials showed that a 10 μg/m3 decrease in PM2.5 translated into a ~2‐mm Hg reduction in systolic BP, more than a 3‐fold greater response.2 Moreover, the relationship between PM2.5 and BP may vary depending on exposure characterization/sources, region, or population susceptibility (eg, race and ethnicity), but this needs to be elucidated in future studies. Although PM2.5 increases the risk for hypertension categorically, it is critically important to evaluate the continuous effect on BP to accurately characterize the full extent of the population health toll.2 Most of the observed BP changes would not result in individuals crossing an arbitrary diagnostic threshold (eg, 140/90 mm Hg) within a limited time period. Nonetheless, such population‐wide shifts in BP pose serious adverse public health effects whether occurring above or below clinical cut points. Although our study has limitations inherent to all ecological analysis, the findings suggest that PM2.5 is a major global risk factor for high BP and adds further support for international efforts to improve air quality.Sources of FundingThis work was supported by the National Institutes of Health grants P50 MD017351‐01 and 1R35ES031702‐01A1.DisclosuresNone.Footnotes*Correspondence to: Robert D. Brook, MD, Division of Cardiovascular Medicine, Department of Internal Medicine, Wayne State University, 400 Mack Avenue, Detroit, MI 48201. Email: [email protected]eduThis article was sent to Tiffany M. Powell‐Wiley, MD MPH, Associate Editor, for review by expert referees, editorial decision, and final disposition.For Sources of Funding and Disclosures, see page 3.References1 GBD 2019 Risk Factors Collaborators . Global burden of 87 risk factors in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet. 2020; 396:1223–1249. doi: 10.1016/S0140-6736(20)30752-2CrossrefMedlineGoogle Scholar2 Newman J, Rajagopalan S, Levy P, Brook RD. Clearing the air to treat hypertension. J Hum Hypertens. 2020; 34:759–763. doi: 10.1038/s41371-020-0358-9CrossrefMedlineGoogle Scholar3 Niu Z, Duan Z, Yu H, Xue L, Liu F, Yu D, Zhang K, Han D, Wen W, Xiang H, et al. Association between long‐term exposure to ambient particulate matter and blood pressure, hypertension: an updated systematic review and meta‐analysis. Int J Environ Health Res. 2022; 33:1–16. doi: 10.1080/09603123.2021.2022106CrossrefGoogle Scholar4 WHO global air quality guidelines: particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. World Health Organization. 2021. Accessed April 4, 2023. https://apps.who.int/iris/handle/10665/345329.Google Scholar5 Global Burden of Disease Collaborative Network . Global Burden of Disease Study 2019 (GBD 2019) Air Pollution Exposure Estimates 1990–2019. Institute for Health Metrics and Evaluation (IHME); 2021. doi: 10.6069/70JS-NC54CrossrefGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails Article InformationMetrics Copyright © 2023 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley BlackwellThis is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.https://doi.org/10.1161/JAHA.122.029206PMID: 37042288 Manuscript receivedJanuary 27, 2023Manuscript acceptedMarch 20, 2023Originally publishedApril 12, 2023 Keywordsair pollutionblood pressurecardiovascular riskenvironmentPDF download SubjectsRisk Factors