Suh M, Mittal L, Hirsch S, Valdes R, Bartlett C, Rohr A, Proctor D. Lung cancer risk in chromate production workers exposed to hexavalent chromium. Presented at the Society of Toxicology’s 54th Annual Meeting, San Diego, CA, March 22-26, 2015 .
The risk of lung cancer among chromate production workers has been used in several quantitative hexavalent chromium [Cr(VI)] risk assessments, and one of the most studied cohorts is from the Painesville Ohio facility. The last follow-up of this cohort was completed in 1997, including 482 workers and 14,048 total person-years at risk. Short-term workers (<1 year of employment) were excluded, limiting information in the low exposure range. We conducted an updated study of 714 Painesville workers employed from 1940-1972, including 198 short-term workers and 47 with unknown vital status at the end of previous follow-up, to calculate standardized mortality ratios (SMRs) and improve upon the data available for cancer risk assessment. The average length of follow-up (through 2011) was 34.4 years, including 24,535 total person-years at risk. Vital status was confirmed for 690 workers (658 deceased, 32 alive); 24 were loss to follow-up. A comprehensive job exposure matrix was used to estimate Cr(VI) exposures for each worker for cumulative exposure and highest monthly exposure, which is the highest exposure estimated. Significant excess in mortality were observed for the entire cohort from cancers of trachea/lung/bronchus (n=77; SMR 186, 95% 145 to 228) and other circulatory system diseases (n=60; SMR 153, 95% 114 to 191). In addition, there was a significant decreasing trend in lung cancer deaths according to year of hire (p=0.04) and an increasing trend by duration of employment (p<0.01). Lung cancer death was significantly elevated in the cohort with increasing Cr(VI) exposure for both highest monthly exposure (p=0.03) and cumulative exposure (p<0.01). Although short-term workers had lower Cr(VI) exposures compared to the entire cohort, they had higher all-cause mortality, which was significant, indicating poorer health status. These data provide new data for dose-response modeling and the cancer risk assessment for airborne Cr(VI).