Occupationally exposures to dust containing silicon dioxide or silica (SiO2) in the crystalline form, cause silicosis, a typical pulmonary fibrotic disease. In silicotic patients there are frequently and very important discordances between the radiological aspect and the presence of ventilatory dysfunctions, even if a lot of studies showed a good correlation between the anatomic alterations and the lung function. The functional alterations of the lung are caused not only by the silicotic lesions but also by accompanying diseases as chronic bronchitis and emphysema. In this study we compared the changes in lung function parameters in foundry workers and miners with, and without silicosis.
We examined 252 foundry workers with the mean age = 34.74±7.9 years, range 18–60 years, and 285 miners with the mean age = 37.95±9.5 years, range 19–60 years. We made clinical and X ray exam, respiratory tests and completed standard questionnaire regarding the respiratory symptoms. The concentration of the total dust and respiratory dust exceeded 30 times the maximum allowable concentration in foundry and 10 times in mine.
We found obstructive ventilatory dysfunction (OVD) in 21.03% foundry workers and 10.87% miners; restrictive ventilatory dysfunction (RVD) in 3.17% foundry workers and 4.21% miners. Simple silicosis (small opacities of different profusion) was presented in 13.88% foundry workers and 6.57% miners. The silicotic workers had obstructive ventilatory dysfunction in proportion of 34.28% and restrictive ventilatory dysfunction in proportion of 2.58%. Regarding the silicotic miners: 21.42% had obstructive ventilatory dysfunction and 14.28% had restrictive ventilatory dysfunction.
There were significant differences regarding the presence of the obstructive ventilatory dysfunctions between foundry workers and miners (p < 0.002) and between silicotic workers in foundry and mine (p < 0.01). Significant differences also appear between the two exposed groups regarding the presence of silicosis (p < 0.001) and the presence of ventilatory dysfunctions in silicotic workers (p < 0.02). The number of silicosis and obstructive ventilatory dysfunctions was greater in foundry workers than in miners, due to the exposure to high concentration of free silica crystal. The study represents an alarm signal regarding the working conditions in foundries and suggests the necessity of decreasing the high silica concentration in the working environment.