Spirometric volumes in Malaysian males

Spirometry was performed on 1,485 male subjects ranging in age from 13 years to 78 years and comprising of all the main ethnic groups in Malaysia. They were divided into six age categories. Mean forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were 3.45 +/- 0.02 and 3.10 +/- 0.02, respectively. Both FVC and FEV1 correlated negatively with age. Regression analysis revealed an age-related decline in FVC of 295 ml per decade of life. Multiple stepwise regression of the data for the prediction of an individual's FVC above the age of 20 years gave the equation FVC (1) = 0.0404 (height in cm)-0.0295 (age in years)-2.2892. Predicted FVC values derived from equations based on other populations were considerably higher than the observed mean in this study. This study therefore, reemphasises the need to be cautions when applying formulae derived from one population to another. Grossly erroneous conclusions may be reached unless predicted equations for lung-function tests for a given population group are derived from studies based upon the same population group.