Lung volumes in normal Cantonese subjects: preliminary studies.

Measurements of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC ratio, functional residual capacity (FRC), total lung capacity (TLC), residual volume (RV), and RV/TLC ratio have been made in 331 normal Cantonese subjects (134 male and 197 female). The results have been expressed in multiple regression equations relating the volumes to age, height, and weight and have been compared with those of other workers. Lung volumes obtained in this study are in general lower for Chinese subjects than those reported for Caucasians. Similar findings for FVC were reported by Chuan and Chia (1969) in Singapore and by Wu and Yang (1962) in Taiwan. Significant differences, however, are noted for FRC, TLC, RV, and RV/TLC between our findings and those of Chuan and Chia. Our series is unbalanced because of an uneven distribution of age groups. In fact in none of the reported studies on Chinese subjects, including that of da Costa (1971), is the series large or balanced. Clearly, further research is required in this ethnic group to get more reliable predictive formulae for lung volumes.