Occupational exposure to ceramic fibers and respiratory health among insulators

Abstract

Background: Of all insulation materials used, including asbestos, refractory ceramic fibers (RCFs) are known to be associated with adverse pleural conditions and lung function decline in insulators, however, whether RCF is associated with other chronic respiratory ailments like asthma and COPD among insulators has not been reported. Methods: In this cross-sectional study, 1046 insulators (mean age 44.6±13.9 years) were screened in the Wellness of Workers (WoW) program in Alberta in which all participants underwent clinical investigation including lung function tests and chest radiography. A questionnaire concerning worker demographics, work history, and respiratory symptoms was also administered. Associations between exposure to RCFs and respiratory conditions were assessed by modified Poisson regression adjusting for gender, age, body mass index, and smoking history. Smoking was also tested as an effect modifier. Results: Of those screened, 913 (87%) were males, and 633 (60%) reported exposure to RCFs. The prevalence of COPD, asthma, asbestos-related lung diseases (ARLDs) and recurrent chest infection was 16%, 15%, 8%, and 46%, respectively. In multiple regression models adjusted for confounders, RCF exposure was associated with increased risk of COPD (relative risk [RR]: 1.62; 95% confidence interval [CI]: 1.17-2.23), ARLDs (1.58; 1.02-2.45), and chest infection (1.34; 1.15-1.55) but not asthma (1.24; 0.92-1.67). No effect modification by smoking was observed. Conclusion: Insulators who were exposed to RCFs were at higher risk of COPD, chest infections, and ARLDs than those not exposed to RCFs. These observations indicate that RCFs may pose a greater risk to insulator health than previously recognized.