No=661; M=23.2 No=661; M=4.2 those who discontinued fibre/mL-year years work (discontinued asbestos exposure) and Mining exposure Mining exposure continued work (asbestos between the 1st between the 1st and exposure) <5 years of and 2nd X-ray: 2nd X-ray: asbestos exposure and in exposure after 1st exposure after 1st those with <5 X-Ray X-Ray cumulative exposure Yes=793;M=6.2 Yes=793; M=4.5 a progression of irregular fibre/mL-year years opacities. Authors conclusion: relatively short period of follow up means that the group who continued exposure had only a mean of 4.5 years of exposure and 6.2 fibre-years after the first radiograph and that the time may have been too short for the additional exposure to take effect and the dose too low. Non-significant. Cookson et al RMA ID: Prevalence of 859 mine and mill Crocidolite Cumulative Total days Morbidity study reporting (1986) 000444 Radiographic workers (100% men) mine/mill exposure: 541 worked:541 asbestos exposure Asbestosis in men=9.6 men=126 days producing radiographic 541 = X-ray from 1st Crocidolite changes of small irregular date of employment 318 men=65 days Miners and or small rounded 318 men=5.3 318 = comparison 74 men=101 days Millers at opacities. 299 men = no fibre/mL-year group with no known Average duration of Wittenoom, exposure, 5 = abnormal exposure to crocidolite 74 men followed stay = <4 months Western X-ray and 432 men at the time of X-ray up: 8.1 Australia =exposed had 45 74 = men randomly abnormal X-ray. selected from those Increases in prevalence
No=661; M=23.2 fibre/mL-year Mining exposure between the 1st and 2nd X-ray: exposure after 1st X-Ray Yes=793;M=6.2 fibre/mL-year No=661; M=4.2 years Mining exposure between the 1st and 2nd X-ray: exposure after 1st X-Ray Yes=793; M=4.5 years those who discontinued work (discontinued asbestos exposure) and continued work (asbestos exposure) <5 years of asbestos exposure and in those with <5 cumulative exposure a progression of irregular opacities. Authors conclusion: relatively short period of follow up means that the group who continued exposure had only a mean of 4.5 years of exposure and 6.2 fibre-years after the first radiograph and that the time may have been too short for the additional exposure to take effect and the dose too low. Non-significant. Cookson et al (1986) RMA ID: 000444 Prevalence of Radiographic Asbestosis in Crocidolite Miners and Millers at Wittenoom, Western Australia 859 mine and mill workers (100% men) 541 = X-ray from 1st date of employment 318 = comparison group with no known exposure to crocidolite at the time of X-ray 74 = men randomly selected from those Crocidolite mine/mill Cumulative exposure: 541 men=9.6 318 men=5.3 fibre/mL-year 74 men followed up: 8.1 Total days worked:541 men=126 days 318 men=65 days 74 men=101 days Average duration of stay = <4 months Morbidity study reporting asbestos exposure producing radiographic changes of small irregular or small rounded opacities. 299 men = no exposure, 5 = abnormal X-ray and 432 men =exposed had 45 abnormal X-ray. Increases in prevalence