Different respiratory phenotypes are associated with isocyanate exposure in spray painters

Abstract

Associations have been observed between exposure to isocyanates, consisting mainly of oligomers, and respiratory symptoms and isocyanate specific sensitisation 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 nitric oxide (eNO) in a subset of spray painters.Methacholine challenge and eNO measurements were performed in 229 workers. Questionnaires and blood samples were obtained. Specific immunoglobulin (Ig)E and IgG to hexamethylene di-isocyanate were assessed in serum using various assays. Personal exposure was estimated by combining personal task-based inhalatory exposure measurements and timeactivity information.Workers with higher isocyanate exposure were more often hyperresponsive (prevalence ratio comparing the 75th versus 25th percentile of exposure 1.8). In addition, significant exposurerelated decreased forced expiratory volume in one second (FEV1), FEV1/forced vital capacity ratio and flow-volume parameters independent of BHR were found. BHR was more prevalent among sensitised workers. This was statistically significant for only IgG-ImmunoCAP (Phadia, Uppsala, Sweden) positive workers. eNO was not associated with exposure although slightly elevated eNO levels in specific IgG positive subjects were found.The current study provides evidence that exposure to isocyanate oligomers is related to asthma with bronchial hyperresponsiveness as a hallmark, but also shows independent chronic obstructive respiratory effects resulting from isocyanate exposure.KEYWORDS: Bronchial hyperresponsiveness, hexamethylene di-isocyanate, oligomer, sensitisation, spirometry, spray painter D i-isocyanates are among the most common causes of occupational asthma [1][2][3]. Although asthma is considered the major health effect, hypersensitivity pneumonitis and accelerated lung function decline have also been related to di-isocyanate exposure [4]. Di-isocyanate monomers are characterised by two highly reactive isocyanate (NCO) groups and are used as polymerising agents in polyurethane products [5]. Most of the evidence regarding health effects from di-isocyanates involves these monomers. Lately, isocyanate oligomers or poly-isocyanates, with lower vapour pressure, have been introduced to reduce inhalatory exposure. These are increasingly being used and currently many workers are exposed to complex mixtures of isocyanate oligomers. Exposure assessment for these agents is challenging [6] and few epidemiological studies incorporated an exposure assessment component. As a result, exposure-response information for isocyanate oligomers is extremely limited.The present authors recently demonstrated an association between exposure and (work-related) respiratory symptoms and isocyanate-specific sensitisation in a population of 581 spray painters exposed to mainly hexamethylene di-isocyanate (HDI) oligomers [7]. To further investigate the nature of respirato...

Cleaning sprays, household help and asthma among elderly women

“…The use of cleaning products in spray form has increased in past decades [1]. The harmful effect of products in spray form at home [2], or used by spray painters [3], machine workers [4], or in agriculture [5] at work, have been observed in several diseases. Bello et al [6,7], studying detailed tasks among cleaners, classified the use of cleaning sprays as high risk for inhalation exposure.…”

Evaluation of exposures and health at a specialty chemicals plant, West Virginia.

“…For example, isocyanates, epoxy resins, and methyl methacrylate have been reported to cause or aggravate asthma [NIOSH 2004, Hannu et al 2009, Borak et al 2011. Isocyanates have been studied extensively in the literature, and in addition to asthma, have been associated with hypersensitivity pneumonitis, obstructive lung disease, non-asthmatic neutrophilic bronchitis, and contact dermatitis [NIOSH 2004, Pronk et al 2009, Pala et al 2011. One of the facility's employees was diagnosed with obliterative bronchiolitis, a disease in which the lung's smallest airways are irreversibly scarred, leading to cough and shortness of breath.…”

“…This worker had been potentially exposed to isocyanates during a spill response prior to the onset of symptoms. Some isocyanates are associated with asthma, asthma-like symptoms, and other obstructive lung disease [Pala et al 2011;Pronk et al 2009]. Chemical sensitivity has also been described in the literature; it has been associated with several chemicals used at the plant, including di-isocyanates [Mapp et al 1988].…”

Occupational airborne exposure, specific sensitization and the atopic status: evidence of a complex interrelationship

“…Tarlo et al [11] and Pronk [12] reported a negative association between atopy and asthma development, whereas others found no evidence of an association [13] or a positive one [14]. …”