1 Alif SM, et al. Thorax 2017;0:1–8. doi:10.1136/thoraxjnl-2016-209665 ORIGINAL ARTICLE Occupational exposure to pesticides are associated with ixed airlow obstruction in middle-age Sheikh M Alif, 1 Shyamali C Dharmage, 1,2 Geza Benke, 3 Martine Dennekamp, 3,4 John A Burgess, 1 Jennifer L Perret, 1,5 Caroline J Lodge, 1 Stephen Morrison, 6 David Peter Johns, 7 Graham G Giles, 1,2,8 Lyle C Gurrin, 1,2 Paul S Thomas, 9 John Llewelyn Hopper, 1 Richard Wood-Baker, 7 Bruce R Thompson, 10 Iain H Feather, 11,12 Roel Vermeulen, 13 Hans Kromhout, 13 E Haydn Walters, 1,3,7 Michael J Abramson, 3 Melanie Claire Matheson 1,2 Chronic obstructive pulmonary disease To cite: Alif SM, Dharmage SC, Benke G, et al. Thorax Published Online First: [please include Day Month Year]. doi:10.1136/ thoraxjnl-2016-209665 ► Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ thoraxjnl-2016-209665) For numbered afiliations see end of article. Correspondence to Professor Shyamali C Dharmage, Head of the Allergy and Lung Health Unit, Centre for Epidemiology and Biostatistics, School of Population and Global Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Level 3, 207 Bouverie St, Carlton 3010; s.dharmage@ unimelb.edu.au Received 2 November 2016 Revised 24 April 2017 Accepted 1 May 2017 ABSTRACT Rationale Population-based studies have found evi- dence of a relationship between occupational exposures and Chronic Obstructive Pulmonary Disease (COPD), but these studies are limited by the use of prebronchodilator spirometry. Establishing this link using postbronchodi- lator is critical, because occupational exposures are a modiiable risk factor for COPD. Objectives To investigate the associations between occupational exposures and ixed airlow obstruction using postbronchodilator spirometry. Methods One thousand three hundred and thirty-ive participants were included from 2002 to 2008 follow- up of the Tasmanian Longitudinal Health Study (TAHS). Spirometry was performed and lifetime work history calendars were used to collect occupational history. ALOHA plus Job Exposure Matrix was used to assign occupational exposure, and deined as ever exposed and cumulative exposure unit (EU)-years. Fixed airlow obstruction was deined by postbronchodilator FEV 1 /FVC <0.7 and the lower limit of normal (LLN). Multinomial logistic regressions were used to investigate potential associations while controlling for possible confounders. Results Ever exposure to biological dust (relative risk (RR)=1.58, 95% CI 1.01 to 2.48), pesticides (RR=1.74,95% CI 1.00 to 3.07) and herbicides (RR=2.09,95% CI 1.18 to 3.70) were associated with ixed airlow obstruction. Cumulative EU-years to all pesticides (RR=1.11,95% CI 1.00 to 1.25) and herbicides (RR=1.15,95% CI 1.00 to 1.32) were also associated with ixed airlow obstruction. In addition, all pesticides exposure was consistently associated with chronic bronchitis and symptoms that are consistent with airlow obstruction. Ever exposure to mineral dust, gases/fumes and vapours, gases, dust or fumes were only associated with ixed airlow obstruction in non-asthmatics only. Conclusions Pesticides and herbicides exposures were associated with ixed airlow obstruction and chronic bronchitis. Biological dust exposure was also associated with ixed airlow obstruction in non-asthmatics. Minimising occupational exposure to these agents may help to reduce the burden of COPD. INTRODUCTION Chronic Obstructive Pulmonary Disease (COPD) characterised by postbronchodilator (BD) fixed airflow obstruction (AO) is a chronic debilitating respiratory condition and a growing cause of mortality and morbidity worldwide. 1 Tobacco smoking remains the predominant risk factor for COPD. 2 However, it is now well established that non-smokers also develop COPD and the interest in non-smoking-related risk factors for COPD have exponentially increased in the recent past. 3 Occupational exposures are an important potentially modifiable risk factor for COPD, and while the population-based studies conducted to date have provided valuable information about the impor- tance of these exposures in COPD they have had some important limitations. We recently performed a systematic review assessing the association between occupational exposure to dusts, gases and fumes, and COPD in population-based studies that used job exposure matrices. 4 Our review found an overall association between occupational exposures to mineral dust and gases/fumes and COPD. However, the results varied by definitions of COPD and only one study to date had used post-BD spirom- etry to define COPD. 5 This is an important limitation in the current literature as the post-BD measurement of AO is the gold standard to define fixed AO, 6 which is the hallmark feature of COPD. 1 The one study that did use post-BD to define AO did not find any Key messages What is the key question? ► What are the associations between occupa- tional exposure and ixed airlow obstruction? What is the bottom line? ► This study has shown that pesticides and herbicides exposures were associated with ixed airlow obstruction, chronic bronchitis and respiratory symptoms. Why read on? ► This study is the irst to describe an asso- ciation between all pesticides exposure and ixed airlow obstruction, and certain exposures were only associated with ixed airlow obstruction in non-asthmatics but not in asthmatics. Thorax Online First, published on July 7, 2017 as 10.1136/thoraxjnl-2016-209665 Copyright Article author (or their employer) 2017. Produced by BMJ Publishing Group Ltd (& BTS) under licence. group.bmj.com on July 9, 2017 - Published by http://thorax.bmj.com/ Downloaded from