The Authors: Alison M. Gowers, BSc, MSc, is a member of the Secretariat to the Committee on the Medical Effects of Air Pollutants. Her interests include the application of scientific evidence in risk assessment and policy development. Paul Cullinan, MD, MSc, FRCP, is Professor of Occupational and Environmental Respiratory Disease at Imperial College, London. His interests are in the environmental determinants of lung disease in and out of the workplace. Jon G. Ayres BSc, MD, FRCP, is Professor of Environmental & Respiratory Medicine and Head of the Institute of Occupational and Environmental Medicine, University of Birmingham. He has a long-standing research interest in environmental influences on health in particular lung and heart disease. H. Ross Anderson, MD, MSc, FMedSci, is Professor of Epidemiology and Public Health at St George's, University of London and at King's College, London. His research interests encompass both the epidemiology of asthma and the health effects of air pollution. David P. Strachan, MBChB, MD, FRCP, is Professor of Epidemiology in the Division of Population Health Sciences and Education at St George's, University of London. His research interests include genetics, life course and environmental epidemiology, primarily of respiratory and allergic diseases. Stephen T. Holgate, MD, DSc, FMedSci, is an MRC Professor of Immunopharmacology and Honorary Consultant Physician at the Faculty of Medicine and University of Southampton NHS Foundation Trust. His research interests cover the pathophysiology of asthma and its treatment with an emphasis on translation into patient benefit. Inga C. Mills, BSc, MSc, is a member of the Secretariat to the Committee on the Medical Effects of Air Pollutants. Her interests include air pollution epidemiology. Robert L. Maynard, FRCP, FBTS, is Honorary Professor of Environmental Medicine at the University of Birmingham, UK and was, until 2011, Head of the Air Pollution Unit at the Health Protection Agency (England and Wales). His areas of research interest include respiratory physiology and toxicology with an emphasis on the effects of airborne particles on health.
INVITED REVIEW SERIES: AIR POLLUTION AND LUNG HEALTH†
Does outdoor air pollution induce new cases of asthma? Biological plausibility and evidence; a review
Article first published online: 29 JUL 2012
© 2012 Crown Copyright. Respirology © 2012 Asian Pacific Society of Respirology
Volume 17, Issue 6, pages 887–898, August 2012
How to Cite
GOWERS, A. M., CULLINAN, P., AYRES, J. G., ANDERSON, H. R., STRACHAN, D. P., HOLGATE, S. T., MILLS, I. C. and MAYNARD, R. L. (2012), Does outdoor air pollution induce new cases of asthma? Biological plausibility and evidence; a review. Respirology, 17: 887–898. doi: 10.1111/j.1440-1843.2012.02195.x
SERIES EDITORS: IAN YANG AND STEPHEN HOLGATE
- Issue published online: 29 JUL 2012
- Article first published online: 29 JUL 2012
- Accepted manuscript online: 6 JUN 2012 03:40PM EST
- Received 14 March 2012; accepted 16 March 2012.
- air pollution;
- vehicle emission
It is widely accepted that air pollution can exacerbate asthma in those who already have the condition. What is less clear is whether air pollution can contribute to the initiation of new cases of asthma. Mechanistic evidence from toxicological studies, together with recent information on genes that predispose towards the development of asthma, suggests that this is biologically plausible, particularly in the light of the current understanding of asthma as a complex disease with a variety of phenotypes. The epidemiological evidence for associations between ambient levels of air pollutants and asthma prevalence at a whole community level is unconvincing; meta-analysis confirms a lack of association. In contrast, a meta-analysis of cohort studies found an association between asthma incidence and within-community variations in air pollution (largely traffic dominated). Similarly, a systematic review suggests an association of asthma prevalence with exposure to traffic, although only in those living very close to heavily trafficked roads carrying a lot of trucks. Based on this evidence, the UK's Committee on the Medical Effects of Air Pollutants recently concluded that, overall, the evidence is consistent with the possibility that outdoor air pollution might play a role in causing asthma in susceptible individuals living very close to busy roads carrying a lot of truck traffic. Nonetheless, the effect on public health is unlikely to be large: air pollutants are likely to make only a small contribution, compared with other factors, in the development of asthma, and in only a small proportion of the population.