OBJECTIVESTo compare the difference in pulmonary function between Caucasians and Chinese and assess the best reference values of pulmonary function for Chinese adults.

METHODSValues for pulmonary function were predicted by tests on 4773 Chinese healthy subjects (male: 2560, female: 2213, aged 15-78 years) in six parts (north, northeast, northwest, east, southwest and south) of China. Prediction equations of the European Community for Steel and Coal (ECSC), other equations for overseas Chinese or for Caucasians were also selected. The regression coefficients of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, total lung capacity (TLC) and residual volume (RV) were summarized.

RESULTSECSC predictions were closer to the Chinese ones than other selected equations. Comparison with ECSC predictions showed that on average the values for FVC, FEV1 were 5.3% smaller in Chinese males and 3.3% smaller in Chinese females, with the maximal differences in south China and the minimal differences in North China. RV and TLC in Chinese were lower than in Caucasians (males 4.8%, 5.5%, respectively; females 8.7% and 6.0%, respectively). Conversion factors were given for adjusting ECSC equations to fit Chinese.

CONCLUSIONSFor predicting values of pulmonary function in Chinese, we suggest to use the equations reported here. Alternatively, ECSC regression equations may be used with appropriate conversion factors.

Adolescent ; Adult ; Aged ; Female ; Forced Expiratory Volume ; Humans ; Lung ; physiology ; Male ; Middle Aged ; Reference Values ; Regression Analysis ; Total Lung Capacity ; Vital Capacity

The prognostic role of resting pulmonary hyperinflation as measured by residual volume (RV)/total lung capacity (TLC) in chronic obstructive pulmonary disease (COPD) remains poorly understood. Therefore, this study aimed to identify the factors related to resting pulmonary hyperinflation in COPD and to determine whether resting pulmonary hyperinflation is a prognostic factor in COPD. In total, 353 patients with COPD in the Korean Obstructive Lung Disease cohort recruited from 16 hospitals were enrolled. Resting pulmonary hyperinflation was defined as RV/TLC > or = 40%. Multivariate logistic regression analysis demonstrated that older age (P = 0.001), lower forced expiratory volume in 1 second (FEV1) (P < 0.001), higher St. George Respiratory Questionnaire (SGRQ) score (P = 0.019), and higher emphysema index (P = 0.010) were associated independently with resting hyperinflation. Multivariate Cox regression model that included age, gender, dyspnea scale, SGRQ, RV/TLC, and 6-min walking distance revealed that an older age (HR = 1.07, P = 0.027), a higher RV/TLC (HR = 1.04, P = 0.025), and a shorter 6-min walking distance (HR = 0.99, P < 0.001) were independent predictors of all-cause mortality. Our data showed that older age, higher emphysema index, higher SGRQ score, and lower FEV1 were associated independently with resting pulmonary hyperinflation in COPD. RV/TLC is an independent risk factor for all-cause mortality in COPD.
Aged ; Dyspnea/diagnosis/physiopathology ; Exercise Test ; Exercise Tolerance ; Female ; Forced Expiratory Flow Rates/physiology ; Forced Expiratory Volume ; Humans ; Lung/*physiopathology ; Male ; Middle Aged ; Prognosis ; Pulmonary Disease, Chronic Obstructive/*diagnosis/mortality/physiopathology ; Pulmonary Emphysema/*diagnosis/mortality/physiopathology ; Republic of Korea ; Residual Volume/*physiology ; Respiratory Function Tests ; Surveys and Questionnaires ; Total Lung Capacity/*physiology ; Vital Capacity ; Walking/physiology