Table 2 Spirometry z-scores of the present study population based on the GLI-2012 equations for North East Asians, South East Asians, and individuals of mixed ethnic origin

−0.571 ± 1.512

− 0.703 ± 1.029

−0.695 ± 1.517

−0.743 ± 1.223

0.021 ± 1.177

−0.135 ± 1.089

(−0.759, − 0.382) *

(−0.817, − 0.589) *

(−0.884, − 0.506) *

(−0.880, − 0.607) *

(−0.124, 0.167)

(− 0.257, − 0.014) *

−0.558

− 0.730

−0.619

− 0.819

0.148

− 0.152

(−3.143, 1.855)

(−2.313, 0.799)

(− 3.458, 1.909)

(− 2.797, 1.099)

(− 1.928, 1.798)

(− 1.999, 1.716)

28 (11.2%)

51 (16.1%)

33 (13.3%)

42 (13.5%)

12 (4.8%)

20 (6.4%)

(7.3, 15.1%)

(12.1, 20.1%)

(9.1, 17.5%)

(9.7, 17.3%)

(2.1, 7.5%)

(3.7, 9.1%)

−0.037 ± 1.052

0.105 ± 1.080

0.177 ± 1.002

0.312 ± 1.089

−0.333 ± 1.055

−0.440 ± 1.010

(−0.094, 0.168)

(− 0.014, 0.225)

(0.051, 0.302) *

(0.190, 0.433) *

(−0.465, − 0.201) *

(−0.552, − 0.327) *

0.017

0.126

0.251

0.290

−0.203

−0.462

(−1.736, 1.733)

(−1.619, 1.667)

(− 1.610, 1.899)

(− 1.502, 1.994)

(− 2.073, 1.264)

(− 2.154, 1.239)

13 (5.2%)

8 (2.5%)

12 (4.8%)

10 (3.2%)

23 (9.2%)

31 (10.0%)

(2.4, 8.0%)

(0.8, 4.2%)

(2.1, 7.5%)

(1.2, 5.2%)

(5.6, 12.8%)

(6.7, 13.3%)

−0.101 ± 1.051

− 0.278 ± 1.079

−0.112 ± 1.050

−0.212 ± 1.128

−0.057 ± 1.020

−0.152 ± 1.001

(−0.232, 0.030)

(− 0.397, − 0.159) *

(−0.229, 0.033)

(− 0.338, − 0.086) *

(−0.185, 0.070)

(− 0.264, − 0.040) *

−0.111

− 0.284

−0.051

− 0.266

0.055

− 0.167

(−1.881, 1.591)

(−1.975, 1.282)

(−2.007, 1.702)

(− 2.096, 1.508)

(− 1.745, 1.484)

(− 1.865, 1.547)

18 (7.2%)

20 (6.3%)

20 (8.0%)

25 (8.0%)

15 (6.0%)

20 (6.4%)

(4.0, 10.4%)

(3.6, 9.0%)

(4.6, 11.4%)

(5.0, 11.0%)

(3.1, 8.9%)

(3.7, 9.1%)