RESPIRATORY SYMPTOMS, VENTILATORY IMPAIRMENT, AND BRONCHIAL REACTIVITY IN OIL MIST-EXPOSED AUTOMOBILE WORKERS

Studies concerning the respiratory effects of oil mists are sparse and contradictory. The aim of this study was to determine the respective effects of occupational exposure to straight cutting oils and soluble mineral oils on the prevalence of respiratory symptoms, ventilatory im pairment, and bronchial reactivity. The population study consisted of 308 male workers of a large French car-making plant, including 40 subj ects chronically exposed to straight cutting oils (group S), 51 subjec ts chronically exposed to soluble mineral oils (group E), 139 subjects with chronic dual exposure to straight cutting oils and soluble miner al oils (group D), and 78 unexposed assembly workers used as a control group (group C). Worker evaluation included a standardized questionna ire, measurement of pulmonary function, and a methacholine challenge. Oil mist concentration at the work place was determined by gravimetric analysis. The arithmetic mean concentration was 2.6 +/- 1.8 mg/m(3). The geometric mean concentration was 2.2 +/- 1.9 mg/m(3). The prevalen ce of respiratory symptoms did not differ significantly among the four groups. However, the subjects exposed to straight cutting oils (group S + group D) had a significantly higher prevalence of chronic cough a nd/or phlegm than the others (group E + group O): 25.7% vs. 16.3% (p = 0.048). Furthermore, the prevalence of cough and/or phlegm increased significantly (p = 0.03) with increasing duration of exposure to strai ght cutting oils after adjustment on smoking categories. Lung function tests did not differ significantly among the four groups but we obser ved a significant decrease of forced expiratory volume in 1 sec (FEV(1 )), forced expiratory flow during the middle half of forced vital capa city (FEF(25-75)), and maximal flow rate at 50% and 25% of exhaled for ced vital capacity (V-50 and V-25) according to duration of exposure a mong smokers exposed to straight cutting oils, suggesting a synergisti c effect of tobacco and insoluble oils. No effect of exposure to miner al oils on bronchial reactivity was demonstrated. It is concluded that despite low levels of pollution by oil mists, the present study has s hown tenuous adverse chronic effects of straight cutting oils on respi ratory symptoms and lung function. However, no adverse effect of solub le mineral oils was demonstrated. These results suggest that threshold limit values for mineral oils should be reassessed. (C) 1995 Wiley-Li ss, Inc.