Background: The diffusing capacity of the lung is influenced by multiple factors such as age, sex, height, weight, ethnicity and smoking status. Although a prediction equation for the diffusing capacity of Korea was proposed in the mid-1980s, this equation is not used currently. The aim of this study was to develop a new prediction equation for the diffusing capacity for Koreans. Methods: Using the data of the Korean National Health and Nutrition Examination Survey, a total of 140 nonsmokers with normal chest X-rays were enrolled in this study. Results: Using linear regression analysis, a new predicting equation for diffusing capacity was developed. For men, the following new equations were developed: carbon monoxide diffusing capacity (DLco)=–10.4433–0.1434×age (year)+0.2482×heights (cm); DLco/alveolar volume (VA)=6.01507–0.02374×age (year)–0.00233×heights (cm). For women the prediction equations were described as followed: DLco=–12.8895–0.0532×age (year)+0.2145×heights (cm) and DLco/VA=7.69516–0.02219×age (year)–0.01377×heights (cm). All equations were internally validated by k-fold cross validation method. Conclusion: In this study, we developed new prediction equations for the diffusing capacity of the lungs of Koreans. A further study is needed to validate the new predicting equation for diffusing capacity.
Gold WM. Pulmonary function testing. In: Mason RJ, Broaddus VC, Murray JF, Nadel JA, editors. Murray and Nadel's textbook of respiratory medicine. 4th ed. Philadelphia: Elsevier Saunders; 2005. p. 695-703.
Macintyre N, Crapo RO, Viegi G, Johnson DC, van der Grinten CP, Brusasco V, et al. Standardisation of the single-breath determination of carbon monoxide uptake in the lung. Eur Respir J 2005;26:720-35.
Crapo RO, Gardner RM. DLCO reference equations: a perspective. Am Rev Respir Dis 1986;134:856.
Yang SC, Yang SP, Lin PJ. Prediction equations for singlebreath carbon monoxide diffusing capacity from a Chinese population. Am Rev Respir Dis 1993;147:599-606.
Korotzer B, Ong S, Hansen JE. Ethnic differences in pulmonary function in healthy nonsmoking Asian-Americans and European-Americans. Am J Respir Crit Care Med 2000;161(4 Pt 1):1101-8.
Pesola GR, Huggins G, Sherpa TY. Abnormal predicted diffusion capacities in healthy Asians: an inequality with a solution. Respiration 2006;73:799-807.
Chhabra SK, Kumar R, Gupta UA. Prediction equations for diffusing capacity (transfer factor) of lung for North Indians. Lung India 2016;33:479-86.
Park JO, Choi IS, Park KO. Normal predicted values of singlebreath diffusing capacity of the lung in healthy nonsmoking adults. Korean J Intern Med 1986;1:178-84.
Song EH, Oh YM, Hong SB, Shim TS, Lim CM, Lee SD, et al. Selection of reference equations for lung volumes and diffusing capacity in Korea. Tuberc Respir Dis 2006;61:218-26.
Ra SW, Park TS, Hong Y, Hong SB, Shim TS, Lim CM, et al. Clinical usefulness and the accuracy of Korean reference equation for diffusing capacity. Tuberc Respir Dis 2008;64:80-6.
Burrows B, Kasik JE, Niden AH, Barclay WR. Clinical usefulness of the single-breath pulmonucy diffusing capacity test. Am Rev Respir Dis 1961;84:789-806.
Crapo RO, Morris AH. Standardized single breath normal values for carbon monoxide diffusing capacity. Am Rev Respir Dis 1981;123:185-9.
Paoletti P, Viegi G, Pistelli G, Di Pede F, Fazzi P, Polato R, et al. Reference equations for the single-breath diffusing capacity: a cross-sectional analysis and effect of body size and age. Am Rev Respir Dis 1985;132:806-13.
Roca J, Rodriguez-Roisin R, Cobo E, Burgos F, Perez J, Clausen JL. Single-breath carbon monoxide diffusing capacity prediction equations from a Mediterranean population. Am Rev Respir Dis 1990;141(4 Pt 1):1026-32.
Standardization of lung function tests. Report working party. Bull Eur Physiopathol Respir 1983;19 Suppl 5:1-95.
Korean Center for Disease Control and Prevention. Korean National Health & Nutrition Examination Survey. Cheongju: Korean Center for Disease Control and Prevention; 2017 [cited 2017 Oct 10]. Available from: https://knhanes.cdc.go.kr/knhanes/main.do.
Hwang YI, Park YB, Yoo KH. Recent trends in the prevalence of chronic obstructive pulmonary disease in Korea. Tuberc Respir Dis 2017;80:226-9.
Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al. Standardisation of spirometry. Eur Respir J 2005;26:319-38.
Choi JK, Paek D, Lee JO. Normal predictive values of spirometry in Korean population. Tuberc Respir Dis 2005;58:230-42.