FINDINGS FROM EPIDEMIOLOGICAL STUDIES

Issues Related to Refractory Ceramic Fiber

¨      The University of Cincinnati (UC) medical surveillance study has shown increased levels of respiratory changes in production versus non-production workers.  These changes are similar to those found in workers in other dust-exposed populations and disappear when exposures are removed.

¨      In the UC studies, pleural plaques have been detected in 2.7% (27/1008) of workers.  No pleural changes were identified in workers hired after the study began in 1987.  Note: Pleural plaques are markers of exposure and are not considered evidence of disease.

¨      Cross-sectional, spirometry studies by the UC group revealed decrements in lung function and synergistic effects with smoking.  Although statistically significant, the decrements were not considered clinically significant.  The most recent longitudinal studies have demonstrated that RCF exposures since 1987 have not caused additional decrements in lung function.

¨      Results from an aggressive UC surveillance program between 1952 and 2005 have shown:

o       No excess mortality related to all deaths (SMR = 79),

o       No statistically significant increase in interstitial findings,

o       No increase in lung cancers above that found in the general population,

o       No mesotheliomas, and

o       A slight excess of urinary tract tumors, the significance of which is yet to be determined.

¨      The UC medical surveillance program will continue until 2015.

References:

Cowie HA, Wild P, Beck J, Auburtin G, Piekarski C, Massin N, Cherrie JW, Hurley JF, Miller BG, Groat S and Soutar CA.  (2001).  An epidemiological study of the respiratory health of workers in the European refractory ceramic industry.  Occup Environ Med 58:800-810.

LeMasters C, Lockey J, Rice C, McKay R, Hansen K, Lu J, Levin L, Gartside P. (1994). Radiographic Changes Among Workers Manufacturing Refractory Ceramic Fibre and Products. Ann Occup Hyg 38 (Supplement 1 ). 745-751.

LeMasters GK, Lockey JE, Levin S, McKay RT, Rice CH, Horvath EP, Papes DM, Lu JW, Feldman DJ.  (1998).  An industry-wide pulmonary study of men and women manufacturing refractory ceramic fibers.  Am J Epidemiol 148:910-919.

LeMasters GK, Lockey JE , Yiin JH, Hilbert TJ and Levin LS.  (2003).  Mortality of workers occupationally exposed to refractory ceramic fibers.  Occup Environ Med 45:440-450.

Lockey JE, LeMasters G, Rice C, Hansen K, Levin L, Shipley R, Spitz H, Wiot J.  (1996).  Refractory ceramic fiber exposure and pleural plaques.  Am J Respir Crit Care Med 154(5):1405-10.

Lockey JE, Levin LS, Lemasters GK, McKay RT, Rice CH, Hansen KR, Papes DM, Simpson S, Medvedovic M.  (1998).  Longitudinal estimates of pulmonary function in refractory ceramic fiber manufacturing workers.  Am J Respir Crit Care Med 157(4):1226-1233.

Lockey JE, LeMasters GK, Levin LS, Rice CH, Yiin J, Reutman SS and Papes DM.  (2002).  A Longitudinal Study of Chest Radiographic Changes of Workers in the Refractory Ceramic Fiber Industry.  Chest 121:2044-2051.

Walker AM, Maxim LD and Utell M.  (2002).  Risk analysis for mortality from respiratory tumors in a cohort of refractory ceramic fiber workers.  Regul Toxicol Pharmacol 35:95-104.