Lung function at age 18-25 years: a comparison of different reference value systems

The anthropometrical data of the Caucasian population have significantly changed within the last five decades. The European Community for Coal and Steel (ECCS) assumes a plateau phase and recommends the entry of 25 years old for calculation of reference values in this age range. The question arises if the commonly used reference recommendations for lung function of the ECCS can still be accepted. In the present study standardized spirometric lung function tests were performed by pneumotachography, recording lung volumes and flows (MasterScreen Pneumo, CareFusion, Höchberg) in asymptomatic nonsmoking subjects (202 females, 201 males), aged between 18 and 26, according to the ATS/ERS criteria. The results were compared with the reference recommendations of ECCS, SAPALDIA, LuftiBus, and Bochum (only males). All absolute lung function values showed a correlation (p< 0.05) with height. With respect to FVC and FEV(1), SAPALDIA and Bochum reference values were comparable and close to a 100 (range 97.6-101.4) %pred, whereas both ECCS and LuftiBus showed higher values (range 103.6-109.9%pred). The FEV(1)/FVC ratio was close to a 100 (range 97.6-101.7) %pred in all reference systems, whereas flows showed a wide variability between the reference systems (77.1-114.6%pred), single flows (e.g., 96.9-114.2%pred for MEF(50)) and males/females (males: 93.6-114.6%pred; females: 77.1-107.9%pred). We conclude that SAPALDIA reference values for FVC and FEV(1) should be used, as they better represent lung function in the age group. ECCS and LuftiBus reference values are appreciably (4-10%) lower. Differences between reference systems were less important for the FEV(1)/FVC ratio and lung flows.