An epidemiological study of the respiratory health of workers in the European refractory ceramic fibre industry

Abstract

Objectives-To investigate possible relations between respiratory health and past airborne exposure to refractory ceramic fibres (RCFs) and respirable dust in workers at six European factories, studied previously in 1987. Methods-The target population comprised all current workers associated with RCF production, plus others who had participated in 1987 "leavers". Information was collected on personal characteristics, chest radiographs, lung function, respiratory symptoms, smoking, and full occupational history. Regression analysis was used to study relations between indices of health of individual workers and of cumulative exposure to airborne dust and fibres, and likely past exposure to asbestos. Results and discussion-774 workers participated (90% of current workers, 37% of leavers). Profusion of small opacities in exposed workers (51% 0/1+; 8% 1/0+) was similar to that among an unexposed control group but higher than in new readings of the 1987 study films (11% 0/1+, 2% 1/0+). The large diVerence between 1987 and recent films may be, at least in part, a reading artefact associated with film appearance. Small opacities of International Labour Organisation (ILO) category 1/0+ were not associated with exposure. An association of borderline significance overall between 0/1+ opacities and exposure to respirable fibres was found for some exposure periods only, the time related pattern being biologically implausible. Pleural changes were related to age and exposure to asbestos, and findings were consistent with an eVect of time since first exposure to RCFs. Among men, forced expired volume in 1 second (FEV 1 ) and forced vital capacity (FVC) were inversely related to exposure to fibres, in current smokers only. FEV 1 / FVC ratio and transfer factor (TL CO ) were not related to exposures. The estimated restrictive eVect was on average mild. Prevalence of respiratory symptoms was low. Chronic bronchitis and its associated symptoms (cough, phlegm) showed some association with recent exposure to respirable fibres. This could be due to an irritant eVect of RCFs. (Occup Environ Med 2001;58:800-810)

Co-exposure to refractory ceramic fibres and asbestos and risk of pleural mesothelioma

“…Considering the second hypothesis, while animal studies are in favour of a carcinogenic effect of RCF [2], no epidemiological data are currently available on the carcinogenic potency of RCF [4][5][6]26]. However, RCF are recognised to induce pleural plaques [7][8][9]11], which are considered to FIGURE 1 Nonlinear effect of cumulative index of exposure to asbestos on the logit of pleural mesothelioma in subjects a) exposed only to asbestos or b) exposed to both asbestos and refractory ceramic fibres relative to the minimum cumulative index of exposure. The solid line represents logistic estimates using a four-knot restricted cubic spline function located at the 25th, 50th, 75th and 95th percentiles of cumulative index of exposure to asbestos, adjusted for age and birth cohort using a three-knot restricted cubic spline functions located at the 5th, 50th and 95th percentiles.…”

“…Besides cancer, the European and the US cohort studies of workers exposed to RCF revealed that the prevalence of pleural abnormalities increased with RCF exposure and in the absence of asbestos exposure [7][8][9][10]. More recently, a dose-response pattern was observed between cumulative exposure to RCF and radiographic pleural changes in workers not exposed to asbestos [11].…”

Use of Monte Carlo simulation to investigate uncertainty in exposure modeling

“…This work was carried out as part of a study to investigate the health of workers in the man-made mineral fiber (MMMF) manufacturing industry (10). It was carried out within a vacuum-forming process in which MMMF were processed to form complex shapes.…”

Lung Cytotoxicity of Combined Exposure to Refractory Ceramic Fibres and Cigarette Smoke

“…Cowie at al. 13 found some association between small opacities and cummulative exposure to RCF. Inverse relation between pulmonary function and exposure to fibres was found only in smokers.…”

“…Comparison with control group: * P < 0.05 , ↑ -increase . fied method of Myrvik 13 . After estimation of the viability 14 of AM the bronchoalveolar lavage fluid (BALF) was centrifuged at 400 g for 10 minutes at 4 o C, the cell-free BALF (cfBALF) was transfered into clean cooled glass tubes and the cell sediment adjusted by strerile saline solution to 1×10 6 cells/ml.…”