Are the respiratory health effects found in manufacturers of ceramic fibres due to the dust rather than the exposure to fibres?

OBJECTIVES To determine whether the respiratory symptoms and decrements in lung function found in manufacturers of ceramic fibres are related to exposure to the respirable fibre or inspirable mass constituents of the air in the working environment. METHODS Cross sectional survey of all current European primary producers of ceramic fibre was carried out, with measurement of exposure to respiratory fibres by personal samplers that measured inspirable and total mass, together with a health survey with an expanded respiratory questionnaire and standardised measurement of lung function. Odds ratios were calculated for symptoms and current exposure by multiple logistic regression, and multiple linear regression coefficients for lung function related to cumulative exposures controlled for the effects of respirable fibre and inspirable mass separately and together. RESULTS Significant effects of current exposure to both inspirable dust and respirable fibres were related to dry cough, stuffy nose, eye and skin irritation and breathlessness. The decrements found in smokers and to some extent in ex-smokers in forced expiratory volume in one second and forced expiratory flow from 25% to 75% of expiratory volume, seem to be related to the respirable fibres rather than the inspirable mass constituents of the environment. CONCLUSIONS Current symptoms were related to both current exposure to inspirable dust and respirable fibre. The decrements in lung function were related to the fibre constituent of the exposure.