Impairment of ventilatory function and pulmonary gas exchange in non-smoking coalminers

Indices of ventilatory function and pulmonary gas exchange in 32 non-smoking coalminers (mean age 38.1) were compared with those of 34 non-smoking steelworkers of similar age. The coalminers had significantly lower forced expiratory volume in 1 s (FEV1) and maximum expiratory flow rates and significantly higher residual volume, but similar vital capacity and indices derived from the single-breath test. Pulmonary diffusing capacity for CO and indices of CO2 exchange were similar in both groups. Arterial partial pressure of O2 (PaO2) was significantly lower and alveolar-arterial O2 difference was significantly higher in coalminers than in controls, both at rest and during exercise. There was no relation between lung function and radiological signs of simple pneumoconiosis (10 coalminers had pneumoconiosis). The differences in FEV1 (0.42 l) and in PaO2 (10 mm Hg) between the two groups are the same or larger than those usually found between smokers and non-smokers. Exposure to coaldust may result in biologically significant alterations of lung function even in the absence of pneumoconiosis.