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Background:To report the number of malignant pleural and peritoneal mesotheliomas that have occurred in former Wittenoom crocidolite workers to the end of 2008, to compare this with earlier predictions, and to relate the mesothelioma rate to amount of exposure.Methods:A group of 6489 men and 419 women who had worked for the company operating the former Wittenoom crocidolite mine and mill at some time between 1943 and 1966 have been followed up throughout Australia and Italy to the end of 2008.Results:The cumulative number of mesotheliomas up to 2008 was 316 in men (268 pleural, 48 peritoneal) and 13 (all pleural) in women. There had been 302 deaths with mesothelioma in men and 13 in women, which was almost 10% of all known deaths. Mesothelioma rate, both pleural and peritoneal, increased with time since first exposure and appeared to reach a plateau after about 40 to 50 years. The mesothelioma rate increased with amount of exposure and the peritoneal mesotheliomas occurred preferentially in the highest exposure group, 37% compared with 15% overall.Conclusion:By the end of 2008, the number of mesothelioma deaths had reached 4.7% for all the male workers and 3.1% for the females. Over the past 8 years the numbers were higher than expected. It is predicted that about another 60 to 70 deaths with mesothelioma may occur in men by 2020. [ABSTRACT FROM AUTHOR]

Background: The risk of malignant mesothelioma (MM) increases proportionally to the cumulative exposure, and to the 3rd or 4th power of time since first exposed, to asbestos. However, little is known about the risk of MM after more than 40 years since first exposure because most epidemiological studies do not have follow-up for sufficient periods of time., Methods: The data from six cohort studies of exposed workers and two cohorts with residential exposure have been pooled. A nested case control design matched cases and controls on calendar period and age. Conditional logistic regression modelled the relationship between time since first exposure and risk of MM., Results: The combined data consisted of 22,048 people with asbestos exposure (5769 women), 707 cases of pleural MM (165 in women) and 155 cases of peritoneal MM (32 in women). Median time since first exposure for pleural MM cases was 38.4 years (IQR 31.3-45.3). Median duration of exposure for pleural MM cases was 3.75 years (IQR 0.7-18.2). The rate and risk of pleural MM increased until 45 years following first exposure and then appeared to increase at a slower power of time since first exposure. The rate of increase in peritoneal MM over the 10-50 years since first exposure continued to increase., Conclusions: Exposure to asbestos confers a long-term risk of developing pleural and peritoneal mesothelioma which increases following cessation of exposure. While the rate of increase appears to start to level out after 40-50 years no one survives long enough for the excess risk to disappear., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background: Blue asbestos was mined and milled at Wittenoom in Western Australia between 1943 and 1966., Methods: Nearly 7000 male workers who worked at the Wittenoom mine and mill have been followed up using death and cancer registries throughout Australia and Italy to the end of 2000. Person-years at risk were derived using two censoring dates in order to produce minimum and maximum estimates of asbestos effect. Standardised mortality ratios (SMRs) compare the mortality of the former Wittenoom workers with the Western Australian male population., Results: There have been 190 cases of pleural and 32 cases of peritoneal mesothelioma in this cohort of former workers at Wittenoom. Mortality from lung cancer (SMR = 1.52), pneumoconiosis (SMR = 15.5), respiratory diseases (SMR = 1.58), tuberculosis (SMR = 3.06), digestive diseases (SMR = 1.47), alcoholism (SMR = 2.24) and symptoms, signs and ill defined conditions (SMR = 2.00) were greater in this cohort compared to the Western Australian male population., Conclusion: Asbestos related diseases, particularly malignant mesothelioma, lung cancer and pneumoconiosis, continue to be the main causes of excess mortality in the former blue asbestos miners and millers of Wittenoom.

The crocidolite mine at Wittenoom Gorge, Western Australia, has been active from 1943 to 1966, and managed by Australian Blue Asbestos Ltd (ABA). Migrants constituted the large majority of workers. The list of workers is composed of 6,911 subjects (6,501 males). In it we identified 1,102 Italians (1,069 males) and completed the follow up for those previously lost, remained in Australia or returned to Italy. Up to 1997, 302 subjects (301 males) definitively resettled in Italy, almost always returning to their community of origin. The median length of work at Wittenoom for those resettled was 17.8 months. The resettled subjects are spread around Italy, and 112 subjects (37%) already died. We compared the mortality rates of those returned to Italy to the rates of the male Italian population. Migrants were subjected to a strong selection before departure and were the target of a surveillance program during work at Wittenoom: however, for those resettled, instead of a healthy migrant effect, we observed an overmortality, mainly due to deaths from penumoconiosis (10 deaths vs 0.38 expected), from respiratory tumours (3 deaths from pleural mesothelioma and 4 from primary peritoneal tumours; an excess of lung cancers, SMR 1.28, 95% CI 0.72-2.11, and an excess of undefined caused of deaths (SMR 6.29, 95% CI 2.52-12.96). The study suggests that asbestos-related diseases and deaths have been observed among those resettled to Italy. In order to increase the precision of the follow up of the Wittenoom cohort, a search outside Australia should be carried out in some European countries for workers whose vital status was unconfirmed. Survivors in Italy are suffering from asbestosis, jeopardizing their life, and are at risk of cancer, but few have received information, actions aimed at reducing the accumulated risk, or compensation. Italy had a multi-million number of migrants for work, and an important percentage of migrants is returned to Italy: the effects of occupational exposures to adverse agents should be expected, but this topic has received up to now little attention.

A death-certificate-based case-control study was undertaken covering 249 patients with multiple myeloma diagnosed in Western Australia from 1975 to 1984 whose deaths were registered in Western Australia in the same period (73.4% of the total diagnosed) and 996 control decedents who were matched to the cases by age, sex and death registration district. Death from multiple myeloma was associated with both farming [odds ratio (OR) 1.44 with 95% confidence interval (CI) 0.81-2.55] and woodworking (OR 1.70 with 95% CI 0.67-4.31) but not with farming as the father's occupation (OR 0.96 with 95% CI 0.66-1.41). It was also more frequent in migrants to Australia than in native-born Australians (OR 1.31 with 95% CI 0.99-1.74) particularly those born in England (OR 1.57 with 95% CI 1.11-2.42) and Italy (OR 2.02 with 95% CI 1.09-3.74). An apparent excess of multiple myeloma in all rural residents appeared to be due to bias introduced by matching for death registration district, as rural residents dying from multiple myeloma were more likely to die and have their deaths registered in the city than other rural residents. A conditional logistic regression analysis showed the above associations to be substantially independent of one another.