Spirometry of healthy adult South African men. Part I. Normative values

To determine normative spirometric values for black and white South African men.

A population of 796 bank personnel were subjected to spirometry and anthropometric measurements. An exhaustive questionnaire and radiographic screening process was used to identify a healthy population. Spirometry was performed using two calibrated instruments, a sleeve sealed piston spirometer (Autolink) and a bellows spirometer (Vitalograph). The methodological guidelines of the American Thoracic Society were observed. In the regression analysis Mallow's CP statistic was used to identify the best prediction models.

Compelling evidence was found in support of incorporating sitting height in prediction equations. For the Autolink studies the prediction equations (based on age, standing height and weight) for forced vital capacity (FVC) (litres) were as follows: blacks: 0.053 height-0.030 age- 3.54; and whites: 0.056 height-0.038 age-3.07; for forced expiratory volume in the 1st second (FEV1) (litres) blacks: 0.036 height-0.032 age-1.18; and whites: 0.042 height-0.038 age-1.45. For the Vitalograph the equations were: FVC: blacks 0.048 height-0.024 age- 3.08 L; whites 0.056 height-0.031 age-3.42; FEV1: blacks 0.029 height-0.027 age-0.535; whites 0.042 height-0.036 age-1.84.

The Vitalograph yielded significantly lower values than the Autolink for FVC measurements despite absolute consistency in methods. In view of the fact that the present study was conducted on healthy men, free from noxious industrial exposure, using state-of-the-art methods, these prediction equations may be regarded as the definitive norms for adult South African males.