Pulmonary function indices# | Overall | Males | Females | p-value |
Subjects n | 503 | 243 | 260 | |
FEV1 L | 3.16±0.77 | 3.63±0.71 | 2.72±0.52 | |
FVC L | 3.83±0.88 | 4.45±0.71 | 3.25±0.57 | |
FEV1 % pred | 92±14 | 91±14 | 93±14 | 0.002++ |
FVC % pred | 95±13 | 94±12 | 97±13 | 0.055++ |
FEV1/FVC | 83±9 | 81±10 | 84±8 | 0.019++ |
FEV1/FVC <70% n | 33 (7) | 20 (8) | 13 (5) | 0.144§§ |
FEV1<80% pred n | 84 (17) | 42 (17) | 42 (16) | 0.107§§ |
FEV1 <80% pred¶ n | 43 (9) | 25 (10) | 18 (7) | 0.177§§ |
Bronchial hyperresponsiveness n | ||||
≥12% FEV1 increase post-bronchodilator+ | 16 (3) | 7 (3) | 9 (3) | 0.086§§ |
≥10% FEV1 decrease post-saline diluent§ | 43 (9) | 18 (7) | 25 (10) | 0.269§§ |
Methacholine challenge test PD20 methacholine <0.4 mgƒ | 94 (19) | 37 (15) | 57 (22) | 0.012§§ |
NSBH##,¶¶ | 110 (22) | 44 (18) | 66 (25) | 0.030§§ |
Data are presented as mean±sd or n (%), unless otherwise indicated. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; % pred: % predicted; PD20 methacholine: provocative dose of methacholine causing a ≥20% fall in FEV1; NSBH: nonspecific bronchial hyperresponsiveness. #: pre-bronchodilator values, unless stated otherwise; ¶: using the locally derived reference equation for South African university workers; +: 38 completed the test; §: 465 completed the test; ƒ: 419 completed the test; ##: 457 completed the test; ¶¶: NSBH defined as any of the following two criteria: PD20 methacholine <0.4 or ≥12% increase in FEV1 after administration of a bronchodilator; ++: two-sample unpaired t-test; §§: Chi-squared test with one degree of freedom.