Respiratory effects of exposure to low levels of concrete dust containing crystalline silica.
BACKGROUND
Dusts containing crystalline silica are generated in mining, construction, glass, granite and concrete production industries. The association between exposure to low levels of concrete dust containing crystalline silica and reduction in lung function, was evaluated in a cross-sectional study.


METHODS
The study was carried out among 144 concrete workers, from two factories, with exposure assessment of respirable dust and silica by personal samplers. Results of respiratory questionnaires and standardized measurements of lung function were compared with the results in a control population. Multiple linear regression analysis was used in selecting factors that predict (age and standing height standardized residual) lung function.


RESULTS
The average concentration of respirable dust in both factories was 0.8 mg/m(3) and 0.06 mg/m(3) for respirable silica. The average silica content of the dust was 9%. The average cumulative dust exposure was 7.0 mg/m(3) year and cumulative silica exposure was 0.6 mg/m(3) year. Significant associations between exposure to concrete dust and a small lung function (FEV(1)/FVC ratio, MMEF) loss were found, independent of smoking habits and of a history of allergy.


CONCLUSIONS
Our results indicate that, concrete workers with chronic obstructive pulmonary symptoms and/or work-related lower respiratory symptoms are at risk of having a reduction in lung function (FEV&(1)/FVC ratio) outside the 5th percentile of the external reference population, and therefore, of mild chronic obstructive pulmonary disease, at respirable concrete dust levels below 1 mg/m(3) with a respirable crystalline silica content of 10% (TWA, 8 hr).
Meijer
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Institute for Risk Assessment Science Environmental and Occupational Health Group, University of Utrecht, PO Box 80176, 3508 TD, Utrecht, The Netherlands.
Kromhout
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H
Heederik
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D
D000328:Adult; D003430:Cross-Sectional Studies; D004391:Dust / Q000009:adverse effects*; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D016273:Occupational Exposure / Q000009:adverse effects*; D012044:Regression Analysis; D012129:Respiratory Function Tests; D012822:Silicon Dioxide / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D014797:Vital Capacity
D004391:Dust; D012822:Silicon Dioxide