Similar to the earlier follow-up, 16 only Painesville chromate production workers employed after 31 December 1939 and having a valid social security number and date of birth were included. In this study, we expanded this cohort to include 198 short-term workers who worked <1 year, updated the mortality assessment through 2011, and conducted exposure-response modeling to quantify lung cancer risk from lifetime occupational and continuous environmental exposures to airborne Cr(VI).Īscertainment of Vital Status of the Painesville Cohort and Mortality Analysis 7 However, short-term workers (<1 year of employment) were excluded from the analyses, limiting information in the low exposure range. 7 Extrapolating these findings to a continuous environmental exposure resulted in an environmental unit risk of 0.00978 (90% CI 0.00640–0.0138). From the relative risk model of Poisson regression, the estimated lifetime additional risk of lung cancer mortality associated with 45 years of occupational exposure to 1 μg/m 3 (occupational unit risk) was 0.00205 (90% CI 0.00134–0.00291). 7 A linear exposure-response was observed with cumulative exposure lagged 5 years. (2003), and a significant increase in lung cancer risk was observed at lifetime occupational exposures ⩾1.0 mg/m 3 -years. 7, 16, 17, 18 These data were modeled in Crump et al. 16 As compared with the Mancuso (1975) 12 study, the exposure reconstruction was greatly improved with the use of a job exposure matrix and quantitative measures of airborne Cr(VI). (2003), those employed between 19 with at least 1 year of work tenure ( n=482) were followed through 1997. 12, 14, 15 In a subsequent study of Painesville workers by Luippold et al. 12, 13 However, the exposure characterization for these workers was highly limited. 7, 8, 9, 10, 11 Painesville workers employed from 1931 to 1937 are the basis for the current US Environmental Protection Agency (US EPA) Cr(VI) cancer-risk assessment. 3, 6ĭata from two occupational cohorts-the Painesville, Ohio and Baltimore, Maryland chromate production workers-have been used in several quantitative risk assessments and are also the basis of the Occupational Safety and Health Administration (OSHA) Cr(VI) Rule. 3, 5 Similarly, in Texas ambient Cr(VI) is currently reported to range from 0.0059 to 0.17 ng/m 3. 4 In California, ambient monitoring for Cr(VI) from 1989 to 2013 has shown decreasing levels through time, and current levels generally below 0.1 ng/m 3. 3 Environmental exposures occur in proximity to anthropogenic sources, including emissions from certain industries and combustion of petroleum products (e.g, automobile exhaust). 2 In the EU, the estimated number of Cr(VI)-exposed workers is ~786,000 and that in Canada is 83,000, with the largest numbers exposed by welding. 1 In the United States, >558,000 workers are exposed to airborne Cr(VI). Hexavalent chromium (Cr(VI)) is a known human carcinogen associated with increased lung cancer risk among workers in certain industries. Adjusting for these variables, the occupational unit risk was 0.00166 (95% CI 0.000713–0.00349), and the environmental unit risk was 0.00832 (95% CI 0.00359–0.0174), which are 20% and 15% lower, respectively, than values developed in a previous study of this cohort. Smoking and age at hire were also significant predictors of lung cancer mortality. Of the models assessed, the linear Cox model with unlagged cumulative exposure provided the best fit and was preferred. Lung cancer was significantly increased for the cohort (standardized mortality ratio (SMR)=186 95% confidence interval (CI) 145–228), for those hired before 1959, those with >30-year tenure, and those with cumulative exposure >1.41 mg/m 3-years or highest monthly exposures >0.26 mg/m 3. The average length of follow-up was 34.4 years with 24,535 person-years at risk. We updated the mortality of 714 Painesville workers (including 198 short-term workers) through December 2011, reconstructed exposures, and conducted exposure-response modeling using Poisson and Cox regressions to provide quantitative lung cancer risk estimates. The exposure-response for hexavalent chromium (Cr(VI))-induced lung cancer among workers of the Painesville Ohio chromate production facility has been used internationally for quantitative risk assessment of environmental and occupational exposures to airborne Cr(VI).
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