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Table 1 Characteristics of total subjects and stratified by airflow limitation

From: The association between small airway dysfunction and aging: a cross-sectional analysis from the ECOPD cohort

Characteristics

Total (n = 1859)

Without airflow limitation (n = 1027)

Airflow limitation (n = 832)

P value

Age, y

61.3 ± 8.2

58.5 ± 7.9

64.7 ± 7.1

 < 0.001

Male sex, %

1375 (74.0)

613 (59.7)

762 (91.6)

 < 0.001

BMI, kg/m2

22.7 ± 3.2

23.3 ± 3.2

22.1 ± 3.2

 < 0.001

Educational level, %

   

 < 0.001

 Primary school or less

882 (47.4)

501 (48.8)

381 (45.7)

 

 Middle or high school

927 (49.9)

487 (47.4)

440 (52.9)

 

 College or higher

50 (2.7)

39 (3.8)

11 (1.3)

 

Annual household income, %

   

 < 0.001

 Low

370 (19.9)

174 (16.9)

196 (23.6)

 

 Medium

1286 (69.2)

747 (72.7)

539 (64.9)

 

 High

130 (7.0)

87 (8.5)

43 (5.2)

 

 Unknown

73 (3.9)

19 (1.9)

54 (6.5)

 

Smoking status, %

   

 < 0.001

 Never smoker

649 (34.9)

538 (52.4)

111 (13.4)

 

 Former smoker

385 (20.7)

133 (13.0)

252 (30.2)

 

 Current smoker

825 (44.4)

356 (34.7)

469 (56.4)

 

Smoking index, pack-years

27.3 ± 31.5

19.6 ± 29.0

36.9 ± 31.8

 < 0.001

Smokers living at home, %

732 (39.4)

430 (41.9)

302 (36.3)

0.324

Parental history of respiratory diseases, %

245 (13.2)

91 (8.9)

154 (18.5)

 < 0.001

Occupation exposure > 6 months, %

382 (20.6)

168 (16.4)

214 (25.8)

 < 0.001

Indoor exposure to biomass for cooking or heating, %

662 (35.6)

351 (34.2)

311 (37.4)

0.348

History of comorbidities, %

    

 Asthma

27 (1.5)

5 (0.5)

22 (2.6)

0.007

 Tuberculosis

47 (2.5)

18 (1.8)

29 (3.5)

0.034

 Chronic bronchitis

93 (5.0)

31 (3.0)

62 (7.5)

0.007

History of prior year exacerbation, %

184 (9.9)

63 (6.1)

121 (14.6)

 < 0.001

Respiratory symptoms without colds, %

    

 Cough

520 (27.9)

179 (17.4)

341 (41.0)

 < 0.001

 Sputum

657 (35.3)

248 (24.1)

409 (49.2)

 < 0.001

 Wheeze

209 (11.2)

58 (5.6)

151 (18.1)

 < 0.001

mMRC

0.37 ± 0.62

0.25 ± 0.51

0.52 ± 0.70

 < 0.001

CAT

4.28 ± 6.80

3.64 ± 7.76

5.06 ± 5.28

 < 0.001

Spirometry parameters after bronchodilator use

    

 FEV1/FVC,

69.8 ± 12.9

79.0 ± 5.6

58.3 ± 9.8

 < 0.001

 FEV1, %predicted

87.2 ± 20.2

97.0 ± 14.5

75.1 ± 19.8

 < 0.001

 MMEF, %predicted

50.4 ± 27.7

68.6 ± 23.1

28.0 ± 11.9

 < 0.001

 FEF50, %predicted

56.4 ± 30.5

76.7 ± 24.2

31.2 ± 14.7

 < 0.001

 FEF75, %predicted

40.7 ± 26.6

55.1 ± 27.1

22.9 ± 9.9

 < 0.001

CT parameters

    

 LAA-950, %

2.63 ± 5.36

0.74 ± 1.59

4.96 ± 7.16

 < 0.001

 LAA-856, %

17.0 ± 19.5

7.0 ± 9.9

29.3 ± 21.3

 < 0.001

 RV, L

2.77 ± 1.03

2.23 ± 0.65

3.43 ± 1.03

 < 0.001

 TLC, L

5.04 ± 1.17

4.65 ± 1.06

5.52 ± 1.12

 < 0.001

IOS parameters

    

 R5, Ka/L/s

0.35 ± 0.10

0.33 ± 0.09

0.37 ± 0.13

 < 0.001

 R20, Ka/L/s

0.28 ± 0.07

0.28 ± 0.07

0.27 ± 0.07

0.160

 R5–R20, Ka/L/s

0.07 ± 0.07

0.05 ± 0.04

0.09 ± 0.09

 < 0.001

 X5, Ka/L/s

− 0.12 ± 0.08

− 0.10 ± 0.04

− 0.15 ± 0.10

 < 0.001

 AX, Ka/L

0.68 ± 0.88

0.39 ± 0.33

1.04 ± 1.17

 < 0.001

 Fres, Hz

15.1 ± 5.64

13.1 ± 3.7

17.7 ± 6.5

 < 0.001

  1. Data are expressed as Mean ± SD or n (%) as appropriate. Differences of characteristics between subjects with and without airflow limitation were compared with the Student’s t test, Mann–Whitney U test, the χ2 test, or Fisher exact test as appropriate
  2. BMI body mass index, yrs years; mMRC modified Medical Research Council, CAT COPD Assessment Test; FEV1/FVC the ratio of forced expiratory volume in the first second to forced vital capacity; FEV1,%predicted the ratio of forced expiratory volume in the first second to its predicted value; MMEF, %predicted maximal mid-expiratory flow of percent predicted; FEF50, %predicted and FEF75, %predicted forced expiratory flow at 50 and 75 of forced vital capacity of percent predicted; CT computed tomography; IOS impulse oscillometry; LAA−950 low-attenuation area of the lung with attenuation values below -950 Hounsfield units on full-inspiration CT; LAA-856 low-attenuation area of the lung with attenuation values below -856 Hounsfield units on full-expiration CT; RV residual volume; TLC total lung capacity; IOS impulse oscillometry; R5 resistance at 5 Hz; R20 resistance at 20 Hz; R5–R20 the difference from resistance at 5 Hz to resistance at 20 Hz; X5 reactance at 5 Hz; AX reactance area; Fres resonant frequency; % percent
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Respiratory Research

ISSN: 1465-993X

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