Mortality from Lung Cancer and Other Causes in the Chrysotile Asbestos Mines and Mills of Quebec

This study followed people born 1891 to 1920 who worked at least one month for Quebec's chrysotile asbestos mining companies, in mines, mills or a small factory. Of 11,788 people, 10,421 were traced; 2,457 had died. Each worker's dust index combined the time spent in each job with that job's estimated dust level. Men in the highest dust category, about 5% of the group, had all-cause death rates about 20% above the rest. Most excess respiratory deaths were ascribed to pneumoconiosis. Lung cancer death rates per 1000 men were 6.7 at the lowest exposure amount and duration, and 35.3 at the highest. Uneven tracing and autopsy rates may have exaggerated this gap, the authors noted. They were inclined to conclude that the true difference may well be closer to threefold than fivefold. Three deaths from malignant mesothelial tumours were found. Noting that figures from two other studies were not entirely comparable, the authors wrote that the findings strongly suggest one of two explanations. Either chrysotile is less likely than forms such as crocidolite to cause malignant lung and pleural disease, or insulation and processing workers face additional factors.

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From J-M's medical library

This copy comes from the Johns-Manville medical library. It was among the papers J-M kept in its medical library without an index entry.

We publish this piece for research and commentary: it shows what the medical literature in a leading asbestos company's own library said on the subject, and when. Our summary above is our own reading of it. The copyright stays with the publisher.