CANCER MORTALITY AMONG MAN-MADE VITREOUS FIBER PRODUCTION WORKERS

We have updated the follow-up of cancer mortality for a cohort study o f man-made vitreous fiber production workers from Denmark, Finland, No rway, Sweden, United Kingdom, Germany, and Italy, from 1982 to 1990. I n the mortality analysis, 22,002 production workers contributed 489,55 1 person-years, during which there were 4,521 deaths. Workers with les s than 1 year of employment had an increased mortality [standardized m ortality ratio (SMR) = 1.45; 95% confidence interval (CI) = 1.37-1.53] . Workers with 1 year or more of employment, contributing 65% of perso n-years, had an SMR of 1.05 (95% CI = 1.02-1.09). The SMR for lung can cer was 1.34 (95% CI = 1.08-1.63, 97 deaths) among rock/slag wool work ers and 1.27 (95% CI = 1.01-1.50, 140 deaths) among glass wool workers . In the latter group, no increase was present when local mortality ra tes were used. Among rock/slag wool workers, the risk of lung cancer i ncreased with time-since-first-employment and duration of employment. The trend in lung cancer mortality according to technologic phase at f irst employment was less marked than in the previous follow-up. We obt ained similar results from a Poisson regression analysis limited to ro ck/slag wool workers. Five deaths from pleural mesothelioma were repor ted, which may not represent an excess. There was no apparent excess f or other categories of neoplasm. Tobacco smoking and other factors lin ked to social class, as well as exposures in other industries, appear unlikely to explain the whole increase in lung cancer mortality among rock/slag wool workers. Limited data on other agents do not indicate a n important role of asbestos, slag, or bitumen. These results are not sufficient to conclude that the increased lung cancer risk is the resu lt of exposure to rock/slag wool; however, insofar as respirable fiber s were an important component of the ambient pollution of the working environment, they may have contributed to the increased risk.