Occupational exposure to soft paper dust and mortality

Abstract

ObjectivesOccupational exposure to soft paper dust is associated with impaired lung function. Whether there is an increased risk for asthma or chronic obstructive pulmonary disease (COPD) is unclear.MethodsWe studied 7870 workers from three Swedish soft paper mills, and defined high-exposed workers, as having been exposed to soft paper dust exceeding 5 mg/m3 for at least 5 years. The remaining workers were classified as ‘low exposed’. Person-years at risk were calculated and stratified according to gender, age and calendar-year. The follow-up time was from 1960 to 2013. The expected numbers of deaths were calculated using the Swedish population as reference and standardised mortality ratios (SMRs) with 95% CIs were assessed.ResultsThere was an increased mortality due to obstructive lung disease (asthma and COPD), among high-exposed workers, SMR 1.89, 95% CI 1.20 to 2.83, based on 23 observed cases. High-exposed workers had an increased mortality from asthma, SMR 4.13, 95% CI 1.78 to 8.14, based on eight observed cases. The increased asthma mortality was also observed among high-exposed men, SMR 4.38, 95% CI 1.42 to 10.2, based on five observed cases. The asthma mortality among low-exposed workers, both men and women, was not increased. The COPD mortality was not clearly increased among high-exposed workers (SMR 1.52, 95% CI 0.85 to 2.50).ConclusionHigh occupational exposure to soft paper dust increases the mortality due to asthma, and the results suggest that soft paper dust levels in workplaces should be below 5 mg/m3.