BackgroundFamily members of asbestos workers are at increased risk of malignant mesothelioma (MM). Although the hazard is established, the magnitude of the risk is uncertain, and it is unclear whether risk is also increased for other cancers. Few cohort studies have been reported.ObjectiveThe “Eternit” factory of Casale Monferrato (Italy), active from 1907 to 1986, was among the most important Italian plants producing asbestos-cement (AC) goods. In this article we present updated results on mortality and MM incidence in the wives of workers at the factory.MethodsWe studied a cohort of 1,780 women, each married to an AC worker during his employment at the factory but not personally occupationally exposed to asbestos. Cohort membership was defined starting from the marital status of each worker, which was ascertained in 1988 from the Registrar’s Office in the town where workers lived. At the end of follow-up (April 2003), 67% of women were alive, 32.3% dead, and 0.7% lost to follow-up. Duration of exposure was computed from the husband’s period of employment. Latency was the interval from first exposure to the end of follow-up.ResultsThe standardized mortality ratio (SMR) for pleural cancer [21 observed vs. 1.2 expected; SMR = 18.00; 95% confidence interval (CI), 11.14–27.52] was significantly increased. Mortality for lung cancer was not increased (12 observed vs. 10.3 expected; SMR = 1.17; 95% CI, 0.60–2.04). Eleven incident cases of pleural MM were observed (standardized incidence ratio = 25.19; 95% CI, 12.57–45.07).ConclusionsHousehold exposure, as experienced by these AC workers’ wives, increases risk for pleural MM but not for lung cancer.

This study of a cohort of asbestos exposed workers with very long follow-up confirmed the reduction in risk of death from lung cancer after the end of exposure. It also suggested a reduction in risk for pleural mesothelioma with over 40 years of latency, while risk for peritoneal mesothelioma showed a continuing increase.