Follow-up of ventilatory lung function in a group of cement workers

In a group of 160 active cement workers and 80 control workers selected on the basis of having or not having symptoms of chronic bronchitis, forced vital capacity (FVC) and one second expiratory volume (FEV 1-0), both corrected for age and height, and ratio of one second forced expiratory volume to forced vital capacity (FEV 1-0/FVC (%)) were measured on two occasions with an interval of four and eight years respectively.