Spirometry reference values for nonexposed blue-collar workers.

Epidemiologic research into occupationally related lung disease often requires the comparison of a study population with an external reference group. To establish such a reference group, carefully selected blue-collar workers who had no obvious adverse occupational pulmonary exposure performed simple spirometry, were administered a standard questionnaire, and had standard chest roentgenograms taken. Prediction equations were established for six pulmonary function indices, and a method is given for using these equations to compare a study group with this external nonexposed group. Asymptomatic nonsmokers with negative roentgenograms were extracted from the overall group, and comparison with published data for other such normal groups indicated that the present group is similar to most of them, indicating that there are no serious biases in the present group.