University of Oulu

Litchfield IJ, Ayres JG, Jaakkola JJK, et al. Is ambient air pollution associated with onset of sudden infant death syndrome: a case-crossover study in the UK. BMJ Open 2018;8:e018341. doi: 10.1136/bmjopen-2017-018341

Is ambient air pollution associated with onset of sudden infant death syndrome : a case-crossover study in the UK

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Author: Litchfield, Ian J1; Ayres, Jon G1; Jaakkola, Jouni J K2;
Organizations: 1Institute of Applied Health Research, College of Medical and Dental Sciences, University of Birmingham
2Center for Environmental and Respiratory Health Research, Faculty of Medicine, University of Oulu
3Medical Research Council Unit The Gambia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.8 MB)
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Language: English
Published: BMJ, 2018
Publish Date: 2018-08-28


Objectives: Air pollution has been associated with increased mortality and morbidity in several studies with indications that its effect could be more severe in children. This study examined the relationship between short-term variations in criteria air pollutants and occurrence of sudden infant death syndrome (SIDS).

Design: We used a case-crossover study design which is widely applied in air pollution studies and particularly useful for estimating the risk of a rare acute outcome associated with short-term exposure.

Setting: The study used data from the West Midlands region in the UK.

Participants: We obtained daily time series data on SIDS mortality (ICD-9: 798.0 or ICD-10: R95) for the period 1996–2006 with a total of 211 SIDS events.

Primary outcome measures: Daily counts of SIDS events.

Results: For an IQR increase in previous day pollutant concentration, the percentage increases (95% CI) in SIDS were 16 (6 to 27) for PM₁₀, 1 (−7 to 10) for SO₂, 5 (−4 to 14) for CO, −17 (−27 to −6) for O₃, 16 (2 to 31) for NO₂ and 2 (−3 to 8) for NO after controlling for average temperature and national holidays. PM₁₀ and NO₂ showed relatively consistent association which persisted across different lag structures and after adjusting for copollutants.

Conclusions: The results indicated ambient air pollutants, particularly PM₁₀ and NO₂, may show an association with increased SIDS mortality. Thus, future studies are recommended to understand possible mechanistic explanations on the role of air pollution on SIDS incidence and the ways in which we might reduce pollution exposure among infants.

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Series: BMJ open
ISSN: 2044-6055
ISSN-E: 2044-6055
ISSN-L: 2044-6055
Volume: 8
Issue: 4
Article number: e018341
DOI: 10.1136/bmjopen-2017-018341
Type of Publication: A1 Journal article – refereed
Field of Science: 3142 Public health care science, environmental and occupational health
Funding: This work was supported by The Lullaby Trust, grant number 260.
Copyright information: © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted. This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: