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. 2016 Jan 5;71(3):255–266. doi: 10.1136/thoraxjnl-2015-207249

Table 5.

Results of spirometry in healthy reference group of participants (n=151)

Men (n=57) Women (n=94) All (n=151) p Value*
Actual median (IQR)
 FEV1 2.0 (1.7–2.4) 1.4 (1.2–1.6) 1.5 (1.2–2.0) <0.001†
 FVC 2.9 (2.4–3.5) 1.9 (1.6–2.2) 2.1 (1.8–2.8) <0.001†
 FEV1/FVC 0.7 (0.6–0.8) 0.7 (0.7–0.8) 0.7 (0.6–0.8) 0.244†
 PEF 515 (340–647) 329.5 (243–417) 367 (263–515) <0.001†
%predicted median (IQR)
 FEV1 90.1 (67.6–103.8) 93.8 (78.6–106.0) 91.6 (76.0–106.0) 0.154†
 FVC 92.3 (72.0–107.7) 101.2 (85.2–121.7) 97.5 (80.6–115.2) 0.006†
Spirometry %(N)
 Normal 38.6 (22) 44.7 (42) 42.4 (64) 0.764‡
 Restrictive 14.0 (98) 12.8 (12) 13.3 (20)
 Obstructive 47.4 (27) 42.6 (40) 44.4 (67)
Obstructive spirometry§ %(N)
 Mild 48.2 (13) 62.5 (25) 56.7 (38) 0.137¶
 Moderate 33.3 (9) 32.5 (13) 32.8 (22)
 Severe 11.1 (3) 5.0 (2) 7.5 (5)
 Very severe 7.4 (2) 0.0 (0) 3.0 (2)
FEV1 %(N)
 Below LLN 21.1 (12) 5.3 (5) 11.3 (17) 0.008**
 Normal range 77.2 (44) 93.6 (88) 87.4 (132)
 Above ULN 1.8 (1) 1.1 (1) 1.3 (2)
FEV1 Z-score
 median (IQR) 0.5 (−0.2–1.6) 0.3 (−0.2–0.9) 0.3 (−0.2–1.0) 0.071†
FVC %(N)
 Below LLN 19.3 (11) 1.1 (1) 8.0 (12) <0.001**
 Normal range 79.0 (45) 91.5 (86) 86.8 (131)
 Above ULN 1.8 (1) 7.5 (7) 5.3 (8)
FVC Z-score
 median (IQR) 0.4 (−0.4–1.5) −0.1 (−0.9–0.6) 0.1 (−0.7–0.9) 0.004†
Oxygen saturation
 median (IQR) 98 (96–98) 98 (97–98) 98 (96–98) 0.970†

*Comparison of men and women.

†Mann–Whitney U test.

‡χ2 test.

§This is based on the 67 participant subsample with obstructive spirometry.

¶Kruskal–Wallis test.

**Fisher's exact test.

LLN, lower limit of normal; PEF, peak expiratory flow; ULN, upper limit of normal.