Peritoneal cancer and occupational exposure to asbestos: results from the application of a job-exposure matrix.

BACKGROUND

Because of the rarity of peritoneal mesothelioma, occupational risks associated with it have seldom been studied, particularly among women. In this respect, death certificates databases may provide numbers large enough for analysis, although the International Classification of Diseases, 9th revision (ICD-9) does not single out mesothelioma from the rest of peritoneal cancers. The aim of this paper is twofold: to explore occupational risks of peritoneal cancer among men and women, and to test the performance of a job-exposure matrix in detecting its association with asbestos exposure using the occupation and industry reported in the death certificate.

METHODS

From a large database containing information on the 1984-1992 death certificates of 24 U.S. states, we identified 657 deaths from peritoneal cancer and 6,570 controls who died from non-malignant diseases, 1:10 matched by region, gender, race, and 5-year age group.

RESULTS

Occupations at risk included insulators among men, and machine operators among women. Among men, we found a significant increase in risk associated with employment in manufacturing industries, such as industrial and miscellaneous chemicals; miscellaneous non-metallic mineral and stone products; construction and material handling machines; and electrical machinery, equipment, and supplies; as well as in services to dwellings and other buildings. Industries at increased risk among women included elementary and secondary schools; miscellaneous retail stores; and publishing and printing. Our job-exposure matrix classified 17 male cases and 3 controls in the high probability category of exposure to asbestos (OR = 61.6). Among men, risk of peritoneal cancer increased significantly by probability and intensity of exposure to asbestos. No such pattern was observed among women. The job-exposure matrix did not classify any female subjects in the high probability or intensity of asbestos exposure.

DISCUSSION

This study provides evidence that death certificate data and job-exposure matrices are useful tools to observe well-established associations, such as the one existing between peritoneal cancer and asbestos exposure among men, in spite of crude information, disease misclassification, and occupational misclassification. These factors are more likely to preclude meaningful results among women.