Different respiratory phenotypes are associated with isocyanate exposure in spray painters

¹ Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands; and Business Unit Quality and Safety, TNO Quality of Life, Zeist, The Netherlands
² Business Unit Quality and Safety, TNO Quality of Life, Zeist, The Netherlands
³ Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
⁴ Netherlands Expertise Centre for Occupational Respiratory Disorders, Heart Lung Centre Utrecht, The Netherlands
⁵ Dept of Pulmonary Diseases, University Medical Centre Utrecht, The Netherlands
⁶ Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands; and Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, The Netherlands

^* To whom correspondence should be addressed. E-mail: D.Heederik{at}iras.uu.nl.

	Abstract

Associations have been observed between exposure to isocyanates consisting mainly of oligomers and respiratory symptoms and isocyanate specific sensitization in spray painters. The aim of the present study was to assess associations between isocyanate exposure and more objective respiratory effect measures such as bronchial hyperresponsiveness (BHR), baseline spirometry and exhaled NO (eNO) in a subset of that population.

Methacholine challenge and eNO measurements were performed in 229 workers. Questionnaires and blood samples were obtained. Specific IgE and IgG to HDI were assessed in serum using various assays. Personal exposure was estimated by combining personal task-based inhalatory exposure measurements and time-activity information.

Workers with higher isocyanate exposure were more often hyperresponsive (prevalence ratio comparing the 75^th versus 25^th percentile of exposure: 1.8, p<0.05). In addition, significant exposure-related decreased FEV₁, FEV₁/FVC and flow-volume parameters independent of BHR were found. BHR was more prevalent among sensitized workers. This was statistically significant for IgG-ImmunoCAP positives only. eNO was not associated with exposure although slightly elevated eNO levels in specific IgG positive subjects were found.

This study provides evidence that exposure to isocyanate oligomers is related to asthma with BHR as a hallmark, but also shows independent chronic obstructive respiratory effects resulting from isocyanate exposure.