Ethnic Differences in Lung Function: evidence for proportional differences

In a group of 244 male low-exposure asbestos cement workers without major clinical symptoms or radiographic changes, marked ethnic differences were found in the relations of lung function to age and height. There is anthropometric evidence that, for given height, whites, of European descent, have a 13.2 per cent larger chest volume at full inspiration than blacks, of African descent, and this accounts almost completely for the differences in total lung capacity, vital capacity, forced vital capacity, forced expiratory volume, forced expiratory flow rate and alveolar volume between blacks and whites. Smaller differences occur for functional residual capacity, residual volume, diffusing capacity (transfer factor) and the diffusion constant. It is proposed that, until further evidence is forthcoming, for normal values a scaling factor of 1. 132 should be used for the major lung volumes to account for the ethnic differences between Africans and Europeans. Smaller scaling factors are proposed for other lung function indices.