University of Oulu

Kai Chen, Susanne Breitner, Kathrin Wolf, Massimo Stafoggia, Francesco Sera, Ana M Vicedo-Cabrera, Yuming Guo, Shilu Tong, Eric Lavigne, Patricia Matus, Nicolás Valdés, Haidong Kan, Jouni J K Jaakkola, Niilo R I Ryti, Veronika Huber, Matteo Scortichini, Masahiro Hashizume, Yasushi Honda, Baltazar Nunes, Joana Madureira, Iulian Horia Holobâcă, Simona Fratianni, Ho Kim, Whanhee Lee, Aurelio Tobias, Carmen Íñiguez, Bertil Forsberg, Christofer Åström, Martina S Ragettli, Yue-Liang Leon Guo, Bing-Yu Chen, Shanshan Li, Ai Milojevic, Antonella Zanobetti, Joel Schwartz, Michelle L Bell, Antonio Gasparrini, Alexandra Schneider, Ambient carbon monoxide and daily mortality: a global time-series study in 337 cities, The Lancet Planetary Health, Volume 5, Issue 4, 2021, Pages e191-e199, ISSN 2542-5196,

Ambient carbon monoxide and daily mortality : a global time-series study in 337 cities

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Author: Chen, Kai1; Breitner, Susanne2,3; Wolf, Kathrin2;
Organizations: 1Yale Sch Publ Hlth, Dept Environm Hlth Sci, New Haven, CT 06520 USA.
2German Res Ctr Environm Hlth, Inst Epidemiol, Helmholtz Zentrum Munchen, Neuherberg, Germany.
3Ludwig Maximilians Univ Munchen, Inst Med Informat Proc, Biometry & Epidemiol, Munich, Germany.
4Lazio Reg Hlth Serv, Dept Epidemiol, Rome, Italy.
5London Sch Hyg & Trop Med, Dept Publ Hlth Environm & Soc, London, England.
6Univ Florence, Dept Stat Comp Sci & Applicat G Parenti, Florence, Italy.
7Univ Bern, Inst Social & Prevent Med, Bern, Switzerland.
8Univ Bern, Oeschger Ctr Climate Change Res, Bern, Switzerland.
9Monash Univ, Sch Publ Hlth & Prevent Med, Air Qual Res Unit, Melbourne, Vic, Australia.
10Shanghai Jiao Tong Univ, Shanghai Childrens Med Ctr, Sch Med, Shanghai, Peoples R China.
11Anhui Med Univ, Sch Publ Hlth, Inst Environm & Populat Hlth, Hefei, Peoples R China.
12Queensland Univ Technol, Sch Publ Hlth & Social Work, Brisbane, Qld, Australia.
13Nanjing Med Univ, Ctr Global Hlth, Sch Publ Hlth, Nanjing, Peoples R China.
14Hlth Canada, Air Hlth Sci Div, Ottawa, ON, Canada.
15Univ Ottawa, Sch Epidemiol & Publ Hlth, Ottawa, ON, Canada.
16Univ Los Andes, Fac Nursing & Midwifery, Santiago, Chile.
17Fudan Univ, Minist Hlth, Key Lab Hlth Technol Assessment, Sch Publ Hlth,Key Lab Publ Hlth Safety Minist Edu, Shanghai, Peoples R China.
18Fudan Univ, Shanghai Key Lab Atmospher Particle Pollut & Prev, Shanghai, Peoples R China.
19Univ Oulu, Ctr Environm & Resp Hlth Res CERH, Oulu, Finland.
20Univ Oulu, Bioctr Oulu, Oulu, Finland.
21Finnish Meteorol Inst, Helsinki, Finland.
22Univ Pablo Olavide, Dept Phys Chem & Nat Syst, Seville, Spain.
23Potsdam Inst Climate Impact Res, Potsdam, Germany.
24Univ Tokyo, Grad Sch Med, Dept Global Hlth Policy, Tokyo, Japan.
25Univ Tsukuba, Fac Hlth & Sport Sci, Tsukuba, Ibaraki, Japan.
26Inst Nacl Satide Dr Ricardo Jorge, Dept Epidemiol, Lisbon, Portugal.
27Univ Nova Lisboa, Ctr Invet Saude Publ, Escola Nacl Saude Publ, Lisbon, Portugal.
28Inst Nacl Saude Dr Ricardo Jorge, Dept Enviromental Hlth, Porto, Portugal.
29Univ Porto, EPI Unit, Inst Saude Publ, Porto, Portugal.
30Babes Bolay Univ, Fac Geog, Cluj Napoca, Romania.
31Univ Torino, Dept Earth Sci, Turin, Italy.
32Seoul Natl Univ, Grad Sch Publ Hlth, Seoul, South Korea.
33Spanish Council Sci Res, Inst Environm Assessment & Water Res, Barcelona, Spain.
34Nagasaki Univ, Sch Trop Med & Global Hlth, Nagasaki, Japan.
35Univ Valencia, Dept Stat & Computat Res, Madrid, Spain.
36Ciberesp, Madrid, Spain.
37Umea Univ, Dept Publ Hlth & Clin Med, Umea, Sweden.
38Swiss Trop & Publ Hlth Inst, Basel, Switzerland.
39Univ Basel, Basel, Switzerland.
40Natl Taiwan Univ, Environm & Occupat Med, NTU Hosp, Taipei, Taiwan.
41Natl Inst Environm Hlth Sci, Natl Hlth Res Inst, Zhunan, Taiwan.
42Harvard TH Chan Sch Publ Hlth, Dept Environm Hlth, Boston, MA USA.
43Yale Univ, Sch Environm, New Haven, CT USA.
44London Sch Hyg & Trop Med, Ctr Stat Methodol, London, England.
45London Sch Hyg & Trop Med, Ctr Climate Change & Planetary Hlth, London, England.
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2021-05-19


Background: Epidemiological evidence on short-term association between ambient carbon monoxide (CO) and mortality is inconclusive and limited to single cities, regions, or countries. Generalisation of results from previous studies is hindered by potential publication bias and different modelling approaches. We therefore assessed the association between short-term exposure to ambient CO and daily mortality in a multicity, multicountry setting.

Methods: We collected daily data on air pollution, meteorology, and total mortality from 337 cities in 18 countries or regions, covering various periods from 1979 to 2016. All included cities had at least 2 years of both CO and mortality data. We estimated city-specific associations using confounder-adjusted generalised additive models with a quasi-Poisson distribution, and then pooled the estimates, accounting for their statistical uncertainty, using a random-effects multilevel meta-analytical model. We also assessed the overall shape of the exposure–response curve and evaluated the possibility of a threshold below which health is not affected.

Findings: Overall, a 1 mg/m³ increase in the average CO concentration of the previous day was associated with a 0·91% (95% CI 0·32–1·50) increase in daily total mortality. The pooled exposure–response curve showed a continuously elevated mortality risk with increasing CO concentrations, suggesting no threshold. The exposure–response curve was steeper at daily CO levels lower than 1 mg/m³, indicating greater risk of mortality per increment in CO exposure, and persisted at daily concentrations as low as 0·6 mg/m³ or less. The association remained similar after adjustment for ozone but was attenuated after adjustment for particulate matter or sulphur dioxide, or even reduced to null after adjustment for nitrogen dioxide.

Interpretation: This international study is by far the largest epidemiological investigation on short-term CO-related mortality. We found significant associations between ambient CO and daily mortality, even at levels well below current air quality guidelines. Further studies are warranted to disentangle its independent effect from other traffic-related pollutants.

Funding: EU Horizon 2020, UK Medical Research Council, and Natural Environment Research Council.

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Series: The Lancet. Planetary health
ISSN: 2542-5196
ISSN-E: 2542-5196
ISSN-L: 2542-5196
Volume: 5
Issue: 4
Pages: e191 - e199
DOI: 10.1016/S2542-5196(21)00026-7
Type of Publication: A1 Journal article – refereed
Field of Science: 3142 Public health care science, environmental and occupational health
Funding: This study was supported by the European Union's Horizon 2020 Project Exhaustion (grant ID 820655), UK Medical Research Council (MR/R013349/1), and UK Natural Environment Research Council (NE/R009384/1). JM was supported by the Fundação para a Ciência e a Tecnologia through the scholarship SFRH/ BPD/115112/2016. VH received funding from the Spanish Ministry of Economy, Industry and Competitiveness (PCIN-2017-046), and the German Federal Ministry of Education and Research (01LS1201A2). YG was supported by a Career Development Fellowship of the Australian National Health and Medical Research Council (APP1163693). SL was supported by an Early Career Fellowship of the Australian National Health and Medical Research Council (APP1109193). ST was supported by the Shanghai Municipal Science and Technology Commission (grant 18411951600).
Copyright information: © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license.