Prevalence of asthma and exhaled nitric oxide are increased in bleachery workers exposed to ozone

Abstract

The aims of the present study were to determine whether exposure to high peaks of ozone resulted in an increased prevalence of asthma or respiratory symptoms among bleachery workers and whether nitric oxide (NO) was elevated in the exhaled air of these workers.Bleachery workers (n=228) from three Swedish pulp mills who had been exposed to ozone, together with 63 unexposed control subjects, were investigated by means of spirometry, Phadiatop1, exhaled and nasal NO and answers to a questionnaire concerning respiratory symptoms and exposure. Exposure to an ozone peak that gave rise to respiratory symptoms was defined as a "gassing".Bleachery workers reporting four or more gassings involving ozone had an increased prevalence of adult-onset asthma, wheeze, and current asthma symptoms. They also had a higher median concentration of exhaled NO in comparison with those who reported no such gassings (19.2 versus 15.7 parts per billion). No such associations were found in respect of nasal NO.The results from this study show that bleachery workers who have been repeatedly exposed to ozone gassings have an increased prevalence of adult-onset asthma. The results also indicate exhaled nitric oxide may be a marker of airway inflammation in bleachery workers who have been exposed to high peaks of ozone.

Incidence of asthma among workers exposed to sulphur dioxide and other irritant gases

“…There is a longitudinal study from Quebec, Canada, showing that Cl 2 gassings increase airway responsiveness [26,27]. OLIN and coworkers [28][29][30] found increased nitric oxide in exhaled air among bleachery workers reporting ozone gassings, which may indicate chronic airway inflammation. Irritants are known to trigger inflammation through epithelial injury, but it has also been proposed that neuronal activity through neuropeptides gives rise to, and maintains, inflammation (i.e.…”

Airflow limitation and changes in pulmonary function among bleachery workers

“…In another round of field studies conducted several years later, the sample size was increased by including workers from a third pulp mill that used ozone. The bleachery workers who reported at least four ozone gassings had a lower FEV1 than the comparison paper mill workers (99.9% versus 105.3% pred), but this difference was not statistically significant (p50.17) [16].…”

“…Of those invited, 76% of the bleachery workers (n5183) performed spirometry testing. Using the same methods at follow-up surveys during 1998-1999 [16], 179 bleachery workers repeated spirometry testing. One bleachery worker was excluded as an outlier for body weight, which left a total of 178 bleachery workers (74%) in the exposed group whose data were included in the final analyses of the present study.…”

“…Of those invited, 63 of the paper mill workers performed spirometry testing. At follow-up during 1998-1999 [16], 62 paper mill workers (67%) repeated spirometry testing. Eight paper mill workers were excluded because they reported a history of gassings while working in pulp mills, which left a total of 54 paper mill workers (58%) for final analysis in this study.…”

“…The bleachery and paper mill workers identified for this study had participated in field studies conducted in the 1990s [15][16][17]. During 1995-1996, researchers invited all process, maintenance, and laboratory workers in the bleaching departments (n5240) from three sulphate pulp mills to participate in a medical survey [15,17].…”