This cross-sectional study was conducted in 1992 in the oldest of three Por
tland cement producing factories in Eastern Saudi Arabia. The respirable du
st level was in excess of the recommended ACGIH level in ail sections. Spir
ometry was done for 149 cement workers and 348 controls, using a Vitalograp
h(R) spirometer. FEV1, FVC, FEV1/FVC% and FEF25-75% were calculated and cor
rected to BTPS. A significantly higher post-shift reduction in FEV1, FEV1/F
VC% 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 lead
ing to some degree of bronchoconstriction as a result of an irritant effect
induced by the acute exposure to cement dust.