PRELIMINARY-ANALYSIS OF PROPORTIONAL MORTALITY IN A COHORT OF BRITISHPOTTERY WORKERS EXPOSED TO CRYSTALLINE SILICA

A cohort of 7020 male pottery workers born in 1916-1945 was identified from all employees in dust-exposed trades, subject to medical surveil lance by the Benefits Agency Medical Service of the Department of Soci al Security in Stoke-on-Trent in the United Kingdom. All but 256 (3.6% ) were traced, 1016 (15.0%) had died by 30 June 1992, and death certif icates were obtained for 940 (92.5%) of the fatalities - 122 from resp iratory cancer. After the exclusion of any recorded asbestos exposure, the proportional mortality ratio (PMR) for lung cancer was 1.22 when calculated against national rates (P < 0.02), but the PMR against loca l rates was 1.04. Logistic regression analyses based on 75 nested case -referent pairs for which the required information was available showe d that lung cancer mortality was dominated by smoking and significantl y affected by past asbestos exposure. However, for 47 pairs in which b oth the case and referent had a history of smoking, there was also sig nificant evidence that the risk was related to duration of silica dust exposure in pottery work but not to radiological score.