A 17-year epidemiological study on changes in lung function in toluene diisocyanate foam workers

To determine whether longitudinal declines in ventilatory capacity and the occurrence of respiratory symptoms in workers manufacturing polyurethane foam were related to toluene diisocyanate (TDI) exposure.

A population of workers from 12 UK factories was studied between 1981 and 1986 [8]. A survivor cohort of 251, of whom 217 were in the 1981-1986 study, was examined again in 1997-1998. Modified British Medical Research Council respiratory questionnaires and lung function measurements were completed for each of the 251 subjects at the beginning and end of the 17-year study period. Mean TDI exposures for all jobs in which subjects were employed were assessed and related to their occupational histories.

The annual declines in 1-second forced expiratory volume (FEV(1)) and forced vital capacity (FVC) were not related to TDI exposure, and were typical of those measured in other populations not exposed to TDI. Over the study period the cold-foam handling group ( n=26) showed an increase in breathlessness and a significant excess decline in FVC; the exposed group ( n=175) showed an increase in wheezing (mainly smokers), whilst the low-exposure group ( n=50) showed a decrease in chest illness. Smoking and an increase in body weight both caused excess declines in FEV(1).

This study does not provide evidence that there was any TDI-related decline in FEV(1) or in FVC over a 17-year period in workers exposed to TDI at the levels prevailing in the UK factories that manufactured flexible polyurethane foam.