BACKGROUND: Fibrous tremolite is a widespread amphibole asbestiform mineral, airborne fibres of which constitute an environmental hazard in Libby, Montana, northern California, and elsewhere. AIMS: To determine excess risk from lung cancer, mesothelioma, and all-cause mortality in a cohort of men exposed to tremolite, but no other form of asbestos. METHODS: Mortality by certified cause and various measures of exposure to tremolite and related amphibole fibres was assessed in a cohort of 406 vermiculite mineworkers in Libby, Montana, employed before 1963 and followed until 1999. RESULTS: Total deaths were: lung cancer 44 (SMR 2.40), non-malignant respiratory disease (NMRD) 51 (SMR 3.09), all causes 285 (SMR 1.27); included among the total were 12 deaths ascribed to mesothelioma (4.21% of all deaths). Adjusted linear increments in relative risks (per 100 f/ml.y), estimated by Poisson regression, were: lung cancer (0.36, 95% CI 0.03 to 1.20), NMRD (0.38, 95% CI 0.12 to 0.96), and all deaths (0.14, 95% CI 0.05 to 0.26). CONCLUSIONS: The all-cause linear model would imply a 14% increase in mortality for mine workers exposed occupationally to 100 f/ml.y or about 3.2% for a general population exposed for 50 years to an ambient concentration of 0.1 f/ml. Amphibole fibres, tremolite in particular, are likely to be disproportionately responsible for cancer mortality in persons exposed to commercial chrysotile, but to what extent cannot be readily assessed.
BACKGROUND:Fibrous tremolite is a widespread amphibole asbestiform mineral, airborne fibres of which constitute an environmental hazard in Libby, Montana, northern California, and elsewhere. AIMS: To determine excess risk from lung cancer, mesothelioma, and all-cause mortality in a cohort of men exposed to tremolite, but no other form of asbestos. METHODS: Mortality by certified cause and various measures of exposure to tremolite and related amphibole fibres was assessed in a cohort of 406 vermiculite mineworkers in Libby, Montana, employed before 1963 and followed until 1999. RESULTS: Total deaths were: lung cancer 44 (SMR 2.40), non-malignant respiratory disease (NMRD) 51 (SMR 3.09), all causes 285 (SMR 1.27); included among the total were 12 deaths ascribed to mesothelioma (4.21% of all deaths). Adjusted linear increments in relative risks (per 100 f/ml.y), estimated by Poisson regression, were: lung cancer (0.36, 95% CI 0.03 to 1.20), NMRD (0.38, 95% CI 0.12 to 0.96), and all deaths (0.14, 95% CI 0.05 to 0.26). CONCLUSIONS: The all-cause linear model would imply a 14% increase in mortality for mine workers exposed occupationally to 100 f/ml.y or about 3.2% for a general population exposed for 50 years to an ambient concentration of 0.1 f/ml. Amphibole fibres, tremolite in particular, are likely to be disproportionately responsible for cancer mortality in persons exposed to commercial chrysotile, but to what extent cannot be readily assessed.
Authors: Robert S Wright; Jerrold L Abraham; Philip Harber; Bryan R Burnett; Peter Morris; Phil West Journal: Am J Respir Crit Care Med Date: 2002-04-15 Impact factor: 21.405
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Authors: John Gilmer; Kinta Serve; Chad Davis; Marti Anthony; Robert Hanson; Tanner Harding; Jean C Pfau Journal: Am J Physiol Lung Cell Mol Physiol Date: 2016-04-22 Impact factor: 5.464
Authors: Julie F Hart; Terry M Spear; Tony J Ward; Caitlan E Baldwin; Marissa N Salo; Mohamed I Elashheb Journal: J Environ Public Health Date: 2009-11-23