Environmental Exposure to Crocidolite and Mesothelioma

Abstract

This study aimed to estimate exposure-response relationships for mesothelioma and environmental exposure to crocidolite. All 4,659 former residents of Wittenoom, Western Australia (WA) who lived there between 1943 and 1993 for at least 1 mo and were not directly employed in the crocidolite industry, were followed-up through the WA death, cancer and mesothelioma registries, electoral rolls, and telephone books. In 1992, all subjects who should be traced were sent a questionnaire. Exposure levels were estimated from results of periodic environmental surveys and duration of residence. Incidence rates were standardized to the World Population and Cox Regression was used to estimate the effects of exposure on incidence. To the end of 1993, 27 cases of mesothelioma were diagnosed. Mesothelioma cases stayed longer at Wittenoom, had a higher average intensity of exposure, and a higher cumulative exposure to crocidolite than control subjects. The standardized incidence of mesothelioma was 260 per million person-years, and was similar for males and females. The rate increased significantly with time from first exposure, duration of exposure and cumulative exposure. At these levels of crocidolite exposure, there is a significantly increased risk of mesothelioma, which is dose-dependent.

Cancer incidence among women and girls environmentally and occupationally exposed to blue asbestos at Wittenoom, Western Australia

“…11,13 These sources and the percent of people they identified included: state primary school records (22%), admission and out-patient records from the Wittenoom hospital and General Practitioner (20%), the State Electoral Roll for the Pilbara district (12%) questionnaires sent to ABA workers (14%), participants of a cancer prevention program and associated publicity (18%) and Wittenoom birth records (4%). Other sources included records from the Catholic Church, Wittenoom burial records, employment lists from the school, hotel, police, hospital and banks and information from the Asbestos Diseases Society of WA (10%).…”

“…14 Therefore follow up status at the end of 1993 was; 2,173 (47%) returned a questionnaire, 641 (14%) were participating in the cancer prevention program, 51 (1%) had permanently departed Australia, 460 (10%) were dead, 785 (17%) had not returned a questionnaire and 549 (11%) were not traced since leaving Wittenoom. 13 Where the person remained untraced, did not return a questionnaire or was dead: if they were related to an ABA worker, then dates and place of residence were assumed identical to that of the worker. For those unrelated to an ABA worker, dates of residence were assumed the same as other family members provided that at least one family member had known exposure.…”

“…Dates of residence were taken as those found on the various sources used to establish the cohort for all other residents. 10,13 If the untraced person was the wife of an ABA worker and known to have lived with that worker, it was assumed that she washed his clothes. The residents' cohort was considered complete when comparisons between it and the population of Wittenoom recorded at various census dates showed a close correspondence.…”

Assessment of cancer risks due to environmental exposure to asbestos

“…However, cases in Wittenoom were exposed to a combination of environmental, occupational and domestic exposure to asbestos and it was not possible to separate the effects of these different routes of exposure on the occurrence of MM (Reid et al, 2007;Reid et al, 2008a, b). An earlier study has shown that residents who had lived at least 5 years in the area and were not directly employed in the crocidolite industry had in increased relative risk of 6.7, which was attributed primarily to environmental exposure to asbestos (Hansen et al, 1998). Hence, it remains a question how sources of asbestos pollution in the general environment will influence exposure patterns among citizens living in that area and how well geographic exposure models are able to estimate the magnitude of asbestos exposure at an individual level.…”

Mesotelioma maligno: descripción clínica y radiológica de 45 casos con y sin exposición a asbestos

“…1,2 La primera descripción histológica de éste fue realizada por E. Wagner en 1870, y no fue sino hasta 1960 cuando J.C. Wagner y colaboradores establecieron una vinculación entre el mesotelioma maligno y la exposición a asbestos; así, describieron una enfermedad con un largo periodo de latencia, que afectaba fundamentalmente a mineros y trabajadores de molinos expuestos a crocidolita. [3][4][5] La incidencia del MM en el ámbito mundial es variable. En Estados Unidos de América (EUA) se han notificado 2 200 nuevos casos por año, con un incremento aproximado de 50% en la última década.…”