Reference values of spirometry for adult Chinese in Hong Kong

Abstract

Background The accuracy of reference values of lung function is important for assessment of severity and functional impairment of respiratory diseases. Lung function varies with ethnicity and may also change over time with changes in environmental factors affecting lung development. The aim of the study was to establish update prediction formulae of spirometric parameters for Hong Kong Chinese and to compare the reference values with those derived from other studies on Caucasians and Chinese. Methods Subjects were recruited by random digit dialing, and 70% of respondents who fulfilled recruitment criteria participated. Spirometry was performed according to American Thoracic Society recommendations and the technique was standardized among the eight participating lung function laboratories. Results Evaluable data was obtained from 1089 (494 males and 595 females) healthy non-smokers aged 18 to 80 years. Age and height were found to be the major determinants of spirometric values with a linear decline of height-adjusted values of FEV1 and FVC with age in both sexes. Spirometric values of this population have increased compared to Chinese populations of similar sex, age and height two decades ago. Reference values based on recommended adjustments of data derived from Caucasian populations overestimated the predicted spirometric parameters by about 5–19%. Conclusion Our findings underscore the need to use reference values based on updated data derived from local populations or those matched for ethnicity and other demographic characteristics. (Supported by a Research Grant from the Pneumoconiosis Compensation Fund Board, Hong Kong, and academic input from the Executive Committee, Hong Kong and Macau Chapter, American College of Chest Physicians.)