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Open Access Highly Accessed Research article

Asthma caused by occupational exposures is common – A systematic analysis of estimates of the population-attributable fraction

Kjell Torén1* and Paul D Blanc2

Author Affiliations

1 Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Göteborg, Sweden

2 Division of Occupational and Environmental Medicine, University of California San Francisco, San Francisco, California, USA

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BMC Pulmonary Medicine 2009, 9:7  doi:10.1186/1471-2466-9-7

Published: 29 January 2009



The aim of this paper is to highlight emerging data on occupational attributable risk in asthma. Despite well documented outbreaks of disease and the recognition of numerous specific causal agents, occupational exposures previously had been relegated a fairly minor role relative to other causes of adult onset asthma. In recent years there has been a growing recognition of the potential importance of asthma induced by work-related exposures


We searched Pub Med from June 1999 through December 2007. We identified six longitudinal general population-based studies; three case-control studies and eight cross-sectional analyses from seven general population-based samples. For an integrated analysis we added ten estimates prior to 1999 included in a previous review.


The longitudinal studies indicate that 16.3% of all adult-onset asthma is caused by occupational exposures. In an overall synthesis of all included studies the overall median PAR value was 17.6%.


Clinicians should consider the occupational history when evaluating patients in working age who have asthma. At a societal level, these findings underscore the need for further preventive action to reduce the occupational exposures to asthma-causing agents.