Respiratory cancer and exposure to man-made vitreous fibers: A systematic review

Background Man-made vitreousfibers (MMVF's) have some structural features similar to those found in asbestos. This has lead to concern that exposure to MMVF's could increase the risk of respiratory cancer. Methods Bibliographic resources were used to identify, 10 case-control and 10 cohort studies, which analyzed the relationship between exposure to MMVF's and cancer of the respiratory system. Standardized mortality ratio's (SMR's) were extracted from the cohort studies for a meta-analysis. Results A significant increase in SMR was observed for workers exposed to rock and glass wool, but not in workers exposed to glass filament. Meta-analysis of SMR's after stratification by fiber type resulted in aggregate estimates of risk of 1.23 (95% CI = 1.10-1.38), 1.08(95% CI=0.93-1.26), and 1.32 (95% CI = 1.15-1.52) for exposure to glass wool, glassfilament, and rock wool, respectively. Some or all of the increased mortality could be attributed to tobacco use. Conclusions The results highlight the difficulty of assessing small increases in risk of respiratory cancer potentially caused by occupational exposure in populations with high prevalence of tobacco use. Published 2002 Wiley-Liss, Inc.