Objective: To collect current information of normal adult pulmonary function in Shanghai, and to verify the applicability of the prediction equations for pulmonary function parameters established in 1988.
Methods: Subjects who underwent routine physical check-up were initially screened in Zhongshan Hospital from Jun. 2009 to Feb. 2010. Those who met the enrollment criteria were asked to take pulmonary function tests. A total of 240 subjects with normal pulmonary function and 120 subjects with mild small airway abnormalities were enrolled in this study according to the prediction equations established in 1988. The age of these subjects ranged from 19 to 83 years old, with a mean age of (42 ± 12) years. All subjects were assigned into 6 groups according to their age, with 60 subjects (30 males, 30 females) in each group. Pulmonary function parameters were collected, including VC, FVC, FEV(1), FEV(1)/FVC, PEF, FEF(25%), FEF(50%), FEF(75%), RV, FRC, TLC, RV/TLC, D(LCO) and KCO. New prediction equations for the above 14 parameters were established by multiple regression analysis. The parameters of anthropometry were introduced into the new and the 1988 prediction equations to get 2 groups of prediction values. Comparison of variance and correlation analysis between the new and the old prediction values were conducted.
Results: New prediction equations for normal adult pulmonary function parameters in Shanghai were established. The actually measured parameters were very close to the predicted values: VC (L) 3.6 ± 0.8 vs 3.6 ± 0.8, FVC (L) 3.5 ± 0.9 vs 3.5 ± 0.8, FEV(1) (L) 3.0 ± 0.8 vs 3.0 ± 0.7, FEV(1)/FVC (%) 83.8 ± 3.1 vs 83.3 ± 2.6, PEF (L/s) 7.7 ± 1.9 vs 7.5 ± 1.6, FEF(25%) (L/s) 6.8 ± 1.7 vs 6.7 ± 1.2, FEF(50%) (L/s) 4.0 ± 0.8 vs 3.9 ± 0.7, FEF(75%) (L/s) 1.5 ± 0.7 vs 1.5 ± 0.6, RV (L) 1.6 ± 0.4 vs 1.6 ± 0.3, FRC (L) 2.8 ± 0.4 vs 2.9 ± 0.4, TLC (L) 5.0 ± 1.0 vs 5.0 ± 0.9, RV/TLC (%) 33.1 ± 4.6 vs 32.7 ± 4.5, D(LCO) (ml×min(-1)×mm Hg(-1), 1 mm Hg = 0.133 kPa) 21.2 ± 5.0 vs 21.2 ± 4.3, KCO (ml×min(-1)×mm Hg(-1)) 4.4 ± 0.7 vs 4.5 ± 0.4 (t = -0.856 - 1.673, all P > 0.05). Except D(LCO) and KCO, there was a significant positive correlation between each pair of the predicted values (r = 0.966 - 0.989, all P < 0.01), and the variance between each pair of predicted values was within 5%.
Conclusion: The prediction equations for normal adult pulmonary function parameters established in 1988 is still valid currently for the population in Shanghai.