Using multiple cause of death coding in occupational mortality studies.

Conventional occupational mortality analysis, using underlying cause of death coding, underestimates the contribution of those chronic diseases which are mentioned on the death certificate but which usually do not appear as underlying cause of death. Proportionate occupational mortality analysis, using all the mentioned causes on the Washington State male death records 1968-1984, identified an excess of rheumatoid arthritis in farmers, and asbestosis in plumbers, pipefitters, and steamfitters.