atmospheric measurements were available for the period before 1960. Sullivan RMA ID: Vermiculite, 1672 mine and Vermiculite Cumulative Fibre Duration of Historical cohort Asbestos (2007) 045641 Respiratory mill workers (all mine/mill exposure: concentration exposure: mortality exposure Disease, and men) method used: producing N=1672; N=1672; reporting vermiculite Asbestos Median=8.7 Job-exposure M=4.0 exposure asbestosis seen 40=asbestosis Miners, Exposure In fibre/mL-year matrix (range=1day at ≥50 deaths Based on 22 millers and Libby, exposure -43.1) years 22=asbestosis All deaths: asbestosis deaths processors Montana: index available deaths n=767; Asbestosis SMR increased with Update of a for this and Median= 21.0 deaths: increasing cumulative n=40 Cohort previous fibre/mL-year (5.3% of exposure: Followed May Mortality studies of cohort); <0-49.9 fibre/mL-year Asbestosis: 1982-Dec 2002 Study Libby workers mean exposure (SMR=37.3; n=40; is based on duration of 95% Cl:7.5, 122.3); Median=228.4 fibre count employment SMR for fibre/mL-year data obtained in those with respiratory (worked using Optical asbestosis death was 1.9 for CFE <1year Phase No smoking M=14.6 years < 3.5 fibre/mL-year =36.2 history Contrast 50.0-249.9 fibre/mL-year Microscopy of and worked all asbestiform (SMR =212.6; 95%CI: year ≥1 fibres, of 91.6, 433.2) and ≥250 =244.8 which 6% fibre/mL-year fibre/mL-year were (SMR=749.1; 95% Cl: estimated to 373.0, 1367.8) be tremolite allowing for a 15-year exposure lag More likely than expected to die from asbestosis with employment duration
atmospheric measurements were available for the period before 1960. Sullivan (2007) RMA ID: 045641 Vermiculite, Respiratory Disease, and Asbestos Exposure In Libby, Montana: Update of a Cohort Mortality Study 1672 mine and mill workers (all men) 40=asbestosis deaths 22=asbestosis deaths Followed May 1982-Dec 2002 No smoking history Vermiculite mine/mill Miners, millers and processors Cumulative exposure: N=1672; Median=8.7 fibre/mL-year All deaths: n=767; Median= 21.0 fibre/mL-year Asbestosis: n=40; Median=228.4 fibre/mL-year (worked <1year =36.2 fibre/mL-year and worked ≥1 year =244.8 fibre/mL-year Fibre concentration method used: Job-exposure matrix exposure index available for this and previous studies of Libby workers is based on fibre count data obtained using Optical Phase Contrast Microscopy of all asbestiform fibres, of which 6% were estimated to be tremolite Duration of exposure: N=1672; M=4.0 (range=1day -43.1) years Asbestosis deaths: n=40 (5.3% of cohort); mean duration of employment in those with asbestosis M=14.6 years Historical cohort mortality reporting vermiculite exposure Based on 22 asbestosis deaths SMR increased with increasing cumulative exposure: <0-49.9 fibre/mL-year exposure (SMR=37.3; 95% Cl:7.5, 122.3); SMR for respiratory death was 1.9 for CFE < 3.5 fibre/mL-year 50.0-249.9 (SMR =212.6; 95%CI: 91.6, 433.2) and ≥250 fibre/mL-year (SMR=749.1; 95% Cl: 373.0, 1367.8) allowing for a 15-year exposure lag More likely than expected to die from asbestosis with employment duration Asbestos exposure producing asbestosis seen at ≥50
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