Post-shift changes in pulmonary function in a cement factory in eastern Saudi Arabia

This cross-sectional study was conducted in 1992 in the oldest of three Portland cement producing factories in Eastern Saudi Arabia. The respirable dust level was in excess of the recommended ACGIH level in all sections. Spirometry was done for 149 cement workers and 348 controls, using a Vitalograph® spirometer. FEV,, FVC, FEV,/FVC% and FEF25-75% were calculated and corrected to BTPS. A significantly higher post-shift reduction in FEVi, FEVi / FVC% and FEF25-75% was observed in the exposed subjects. Multiple regression analysis showed a significant relationship between post-shift changes and exposure to cement dust but failed to support any relationship with smoking. These findings may indicate an increase in the bronchial muscle tone leading to some degree of bronchoconstriction as a result of an irritant effect induced by the acute exposure to cement dust.