Asthma characteristics elucidated in cleaning workers
medwireNews: Results from a Spanish study show that asthma in cleaners is characterized by non-reversible airway obstruction and non-eosinophilic inflammation.
The findings, published in Respiratory Medicine, also suggest that eosinophilic inflammation and oxidative stress are unlikely to play a key role in the development of asthma symptoms among cleaners.
"This work contributes to disentangling the physiological characteristics of the respiratory disorders associated to cleaning-related exposures," comment David Viscaya (Centre for Research in Environmental Epidemiology, Barcelona) and team.
The researchers studied 42 cleaners with a history of asthma and/or asthma symptoms (wheeze, chest tightness, breathlessness at rest, breathlessness after exercise, and nocturnal breathlessness) in the past year and 53 cleaners (controls) without any lower tract respiratory symptoms.
All of the participants underwent lung function tests and supplied blood and exhaled breath condensate samples for analysis.
The researchers found that mean forced expiratory volume in 1 second (FEV1), FEV1/forced vital capacity (FVC) ratio, and forced expiratory flow between 25% and 75% of FVC were significantly lower in cleaners with asthma than controls, although there were no significant between-group differences in FVC.
A significantly higher proportion of asthma patients than controls had a percentage of predicted FEV1 below 85% both before (28 vs 11%) and after (25 vs 8%) inhalation of bronchodilator.
In addition, cleaners with asthma were more likely to be atopic than controls, at 42% versus 10%, and their levels of total immunoglobulin E were 2.9-times higher, at 39.7 versus 14.9 IU/mL. These differences remained significant after accounting for gender, age, and smoking status.
There were no significant differences between the groups in levels of other biologic markers, including fraction of exhaled nitric oxide (FeNO), surfactant protein D, and 16 kDa Clara Cell Protein, interleukins, and growth factors.
The researchers note that the occupational and domestic use of multi-use cleaning products, particularly in spray form, was strongly associated with asthma. Furthermore, the occupational use of multiuse products, glass cleaners, and polishes was associated with higher FeNO levels.
Viscaya et al conclude: "Our findings about occupational and domestic exposure to cleaning products… highlight the importance both for general public health and occupational safety.
"Further studies on the mechanisms of asthma in individuals exposed to cleaning agents are recommended."
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By Mark Cowen, Senior medwireNews Reporter