[Influence of exposure time to silica and smoking on pulmonary function of workers in the ceramic and stone quarry industry].

The aim of this study was to analyze the influence of the numbers of years a worker is exposed to silica dust and the smoking habit upon his lung function. In order to be included in this study the worker should have been exposed to silica dust for a minimum of ten years and give his oral consent to have his lung function studied and a chest X-ray done. The study was done with individuals who claimed for compensation for silicosis to the Brazilian National Institute of Social Security during the period from 1973 to 1981, in Jundiaí city, São Paulo state. The study groups were made up of 137 workers: Group I, exposure between 10 and 20 years (44 workers) and Group II, exposure over 20 years (93 workers); 59 (42.4%) workers were cigarette smokers, 53 (38.1%) non-smokers and 27 (19.4%) former smokers. Lung function was accomplished through spirometry (FVC, FEV1, FEV1/FVC and FEF 25-75%) flow volume curves breathing air and helium-oxygen mixture (Vmax 50%, Vmax 25% and VisoV). No difference was found between the two groups concerning radiological chest nodules, spirometry, flow volume curves and smoked packyears; smokers had a worse lung function when compared to the non smokers of the same group. These alterations in Group I smokers were predominantly in the peripheral airways (Vmax 25%--p less than 0.05) whereas in those smokers of Group II large airways were also involved (VisoV, FEV1, FEV1/FVC--p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)