INCIDENCE OF SILICOSIS AMONG CERAMIC WORKERS IN CENTRAL ITALY

The incidence of radiological silicosis was studied among 2480 male wo rkers employed in the ceramics industry. The subjects entered the surv eillance program during 1974-1987 and were followed through 1991 with annual chest radiographs. The cumulative risk of silicosis (1/1 or gre ater; p,q,r) reached 48% (95% confidence interval 41.5-54.9) after 30 years of employment. In a multivariate Cox's proportional hazards mode l, the effect of duration of exposure increased linearly up to the cat egory of 25-29 years; an extremely high hazard risk of 14.6 was found among those with 30 years or more of exposure in comparison with those employed 10 years or less. Smoking habit also significantly contribut ed to the model, although its role in the biological process is unclea r. In conclusion, exposure to silica dust has been associated with a h igh incidence of silicosis among ceramics workers. The risk estimates are consistent with the recent findings of silicosis incidence among S outh African gold miners.