SORA

Advancing, promoting and sharing knowledge of health through excellence in teaching, clinical practice and research into the prevention and treatment of illness

Are environmental risk factors for current wheeze in the International Study of Asthma and Allergies in Childhood (ISAAC) phase three due to reverse causation?

Silverwood, RJ; Rutter, CE; Mitchell, EA; Asher, MI; Garcia-Marcos, L; Strachan, DP; Pearce, N; ISAAC Phase Three Study Group, (2019) Are environmental risk factors for current wheeze in the International Study of Asthma and Allergies in Childhood (ISAAC) phase three due to reverse causation? Clin Exp Allergy, 49 (4). pp. 430-441. ISSN 1365-2222 https://doi.org/10.1111/cea.13325
SGUL Authors: Strachan, David Peter

[img]
Preview
PDF Published Version
Available under License Creative Commons Attribution.

Download (520kB) | Preview
[img]
Preview
PDF Accepted Version
Available under License Creative Commons Attribution.

Download (579kB) | Preview
[img]
Preview
PDF (Supporting information) Accepted Version
Available under License Creative Commons Attribution.

Download (105kB) | Preview

Abstract

BACKGROUND: Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC) measured the global prevalence of symptoms of asthma in children. We undertook comprehensive analyses addressing risk factors for asthma symptoms in combination, at both the individual and the school level, to explore the potential role of reverse causation due to selective avoidance or confounding by indication. OBJECTIVE: To explore the role of reverse causation in risk factors of asthma symptoms. METHODS: We compared two sets of multilevel logistic regression analyses, using (a) individual level exposure data and (b) school level average exposure (ie prevalence), in two different age groups. In individual level analyses, reverse causation is a possible concern if individual level exposure statuses were changed as a result of asthma symptoms or diagnosis. School level analyses may suffer from ecologic confounding, but reverse causation is less of a concern because individual changes in exposure status as a result of asthma symptoms would only have a small effect on overall school exposure levels. RESULTS: There were 131 924 children aged 6-7 years (2428 schools, 25 countries) with complete exposure, outcome and confounder data. The strongest associations in individual level analyses (fully adjusted) were for current paracetamol use (odds ratio = 2.06; 95% confidence interval 1.97-2.16), early life antibiotic use (1.65; 1.58-1.73) and open fire cooking (1.44; 1.26-1.65). In school level analyses, these risk factors again showed increased risks. There were 238 586 adolescents aged 13-14 years (2072 schools, 42 countries) with complete exposure, outcome and confounder data. The strongest associations in individual level analyses (fully adjusted) were for current paracetamol use (1.80; 1.75-1.86), cooking on an open fire (1.32; 1.22-1.43) and maternal tobacco use (1.23; 1.18-1.27). In school level analyses, these risk factors again showed increased risks. CONCLUSIONS & CLINICAL RELEVANCE: These analyses strengthen the potentially causal interpretation of previously reported individual level findings, by providing evidence against reverse causation.

Item Type: Article
Additional Information: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2018 The Authors. Clinical & Experimental Allergy Published by John Wiley & Sons Ltd
Keywords: asthma, environment and hygiene hypothesis, epidemiology, ISAAC Phase Three Study Group, 1107 Immunology, 1117 Public Health And Health Services, Allergy
SGUL Research Institute / Research Centre: Academic Structure > Population Health Research Institute (INPH)
Journal or Publication Title: Clin Exp Allergy
ISSN: 1365-2222
Language: eng
Dates:
DateEvent
28 March 2019Published
23 January 2019Published Online
4 November 2018Accepted
Publisher License: Creative Commons: Attribution 4.0
Projects:
Project IDFunderFunder ID
FP7/2007-2013/ERCFP7 Ideas: European Research CouncilUNSPECIFIED
MR/N013638/1Medical Research Councilhttp://dx.doi.org/10.13039/501100000265
668954European Union's Seventh Framework ProgrammeUNSPECIFIED
097834/Z/11/BWellcome Trusthttp://dx.doi.org/10.13039/100004440
PubMed ID: 30508327
Go to PubMed abstract
URI: http://openaccess.sgul.ac.uk/id/eprint/110356
Publisher's version: https://doi.org/10.1111/cea.13325

Actions (login required)

Edit Item Edit Item