A cohort study on mortality among wives of workers in the asbestos cement industry in Casale Monferrato, Italy

Our plain-English summary of A cohort study on mortality among wives of workers in the asbestos cement industry in Casale Monferrato, Italy, by C. Magnani, B. Terracini, C. Ivaldi, et al (British Journal of Industrial Medicine, 1993).

The study

• Authors: C. Magnani, B. Terracini, C. Ivaldi, M. Botta, P. Budel, A. Mancini, R. Zanetti
• Journal: British Journal of Industrial Medicine
• Published: 1993;50(9):779-84
• Cited by: 54 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The study investigates mortality from cancer and other diseases in a cohort of wives of asbestos cement workers in Casale Monferrato (northwest Italy). After the exclusion of women with an occupational record in the asbestos cement industry, the cohort comprised 1964 women. Their domestic exposure was estimated according to their husbands' periods of employment in the plant: 1740 had a period of domestic exposure whereas the remaining 224 married an asbestos cement worker only after he definitely stopped his activity in the asbestos cement plant; these have, therefore, been considered as unexposed. The cohort of wives was constructed entirely through official records in the town offices and is both exhaustive and unaffected by recall bias. At the end of follow up (1988) 1669 women were alive, 270 were dead and 25 (1.2%) were untraced. Main mortality analyses were only up to age 79 to reduce the misclassification of causes of death. Expected mortality was based on local rates. Mortality analyses were limited to the period 1965-88 due to the availability of local rates: in that period 210 deaths occurred among women with domestic exposure v 229.1 expected. There were four deaths from pleural tumours (one diagnosed as mesothelioma at necropsis) and six from lung cancer v. 0.5 and 4.0 expected respectively. Two further cases of mesothelioma were diagnosed by histological examination after the end of follow up. None of the three wives with histologically diagnosed mesothelioma had been engaged in industrial activities. Corresponding information for the other three cases could not be traced.

In plain English

This retrospective cohort study followed 1964 wives of workers at an asbestos cement plant in Casale Monferrato, Italy, that used chrysotile and crocidolite. Women who had themselves worked at the plant were excluded. Each woman's domestic exposure was estimated from her husband's periods of employment at the plant after marriage. On that basis 1740 women had domestic exposure, and 224 who married after their husbands had stopped working there were treated as unexposed. Deaths before age 80 from 1965 to 1988 were compared with numbers expected from local death rates. Among exposed wives, total deaths (210 v 229.1 expected) and cancer deaths (64 v 73.5) were close to expected. There were four deaths from pleural tumours v 0.5 expected (SMR 792.3, 95% CI 215.9 to 2028.8) and six lung cancer deaths v 4.0 expected. Apart from pleural tumours, no cause of death differed significantly from expected. Two more histologically diagnosed mesotheliomas were found after follow up ended. Husbands of the three women with histological diagnoses said their wives never worked in industry. The authors concluded that the study found a clear excess of mesotheliomas among these wives. They noted that numbers were small and only one of six cases had a necropsy.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective cohort mortality study, with the cohort built from town (municipal) records
• Who was studied: 1964 wives of men employed at the Eternit asbestos cement plant in Casale Monferrato, northwest Italy, after excluding wives with their own employment record at the plant and women who died before 1965. Of these, 1740 had domestic exposure and 224 (married after their husbands stopped working at the plant) were treated as unexposed. Follow up ended 15 February 1988, and mortality was analysed for 1965 to 1988.
• Exposure: Domestic (household) exposure to asbestos from husbands who worked in asbestos cement production. Exposure was estimated from the husband's periods of employment after marriage. The plant used chrysotile and crocidolite throughout its operation, with crocidolite accounting for 10% of asbestos used in 1980. No data were available on asbestos levels in the homes. The plant had no laundering facility, and workers customarily left in their working clothes.
• Main results:
  • Among women with domestic exposure (deaths before age 80), total mortality was 210 observed v 229.1 expected and cancer mortality 64 observed v 73.5 expected, both close to expected.
  • Among women with domestic exposure, there were 4 deaths from pleural tumours v 0.5 expected (SMR 792.3, 95% CI 215.9 to 2028.8).
  • Among women with domestic exposure, there were 6 deaths from lung cancer v 4.0 expected (SMR 149.8, 95% CI 55.0 to 326.1).
  • Apart from pleural malignancies, no cause of death occurred significantly more or less often than expected.
  • Of the four pleural tumour deaths, one had a histological diagnosis of mesothelioma confirmed at necropsy and two were diagnosed by radiological examination; no data were found for the fourth. Two further histologically diagnosed mesothelioma cases were found after follow up ended: one diagnosed in 1988 who died in 1989, and one diagnosed in 1991 who was alive.
  • Husbands of the three histologically diagnosed cases said none of their wives had ever worked in industrial activities. No relative could be found for the other cases.
  • Among women with domestic exposure, no lung or pleural cancer deaths were found before 10 years of latency and 10 years of exposure, and there was no consistent trend with duration or latency. The authors noted the numbers were small.
  • Among the 224 women without domestic exposure, there were 6 deaths v 7.4 expected.
  • Across the whole cohort, married women had reduced mortality regardless of time since marriage. The authors described the link between marriage and health as similar to the healthy worker effect.
• The authors' conclusion: The authors concluded that the study found a clear excess of mesotheliomas among wives of workers in the asbestos cement production industry, and that their results agree with the only similar study published before.
• Limitations the authors state:
  • Only one of six cases had a necropsy, which creates some uncertainty in the diagnoses.
  • The findings on duration of exposure and latency are not conclusive because the numbers are small.
  • The lung cancer figures are too small to support further discussion.
  • No data were available on asbestos exposure inside the women's homes.

Topics

Medical terms in this study, explained in our Lexicon: Cohort Study, Asbestos-Cement, Casale Monferrato, Recall Bias, Mesothelioma, Lung Cancer.

Related studies

• Cancer mortality and incidence of mesothelioma in a cohort of wives of asbestos workers in Casale Monferrato, Italy — D. Ferrante, M. Bertolotti, et al. (2007)
• Mortality in a cohort of cement workers in a plant of Central Italy — F. Giordano, V. Dell'orco, et al. (2012)
• Increased risk of malignant mesothelioma of the pleura after residential or domestic exposure to asbestos: a case-control study in Casale Monferrato, Italy — C. Magnani, P. Dalmasso, et al. (2001)
• Cumulative asbestos exposure and mortality from asbestos related diseases in a pooled analysis of 21 asbestos cement cohorts in Italy — F. Luberto, D. Ferrante, et al. (2019)
• Mortality in asbestos cement workers in Pavia, Italy: A cohort study — E. Oddone, D. Ferrante, et al. (2017)
• Cohort mortality study of rock salt workers in Italy — M. Tarchi, D. Orsi, et al. (1994)

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