Table 1 Demographic and biochemical characteristics of participants at 3 measurement timepoints

Age (years), Mean ± SD

41.5 ± 10.9

45.1 ± 11.0

47.9 ± 11.0

< 0.001

Men, N(%)

6,583(59.3)

6,255(59.6)

3,254(57.4)

0.022

Smoking status, N(%)

< 0.001

 No

7,258(69.0)

6,329(70.8)

3,788(72.5)

 Former

527(5.01)

489(5.47)

310(5.94)

 Current

2,739(26.0)

2,121(23.7)

1,124(21.5)

Physical activity(time/week), N(%)

< 0.001

 < 1

1,788(21.7)

1,533(19.2)

463(12.1)

 1–6

3,944(47.9)

3,502(43.9)

1,653(43.4)

 ≥ 7

2,496(30.3)

2,951(36.9)

1,697(44.5)

Hypertension, N(%)

1,651(14.9)

1,748(16.7)

1,172(20.8)

< 0.001

Diabetic status, N(%)

< 0.001

 Normal

9,310(83.8)

8,630(82.2)

4,557(80.4)

 Prediabetes

1,106(9.96)

1,049(9.99)

597(10.5)

 Diabetes

692(6.23)

823(7.84)

514(9.07)

Total cholesterol(mmol/L), Mean ± SD

4.79 ± 0.89

4.74 ± 0.88

4.76 ± 0.88

< 0.001

BMI (kg/m²),Mean ± SD

24.1 ± 3.55

24.3 ± 3.42

24.4 ± 3.42

< 0.001

Triglycerides (mmol/L), Median (P25-P75)

1.15(0.78–1.72)

1.17(0.82–1.72)

1.22(0.87–1.78)

0.018

FPG(mmol/L), Mean ± SD

5.66 ± 0.98

5.68 ± 1.08

5.74 ± 1.18

< 0.001

HDL(mmol/L), Median(P25-P75)

1.30(1.09–1.57)

1.30(1.09–1.58)

1.34(1.11–1.63)

< 0.001

Diabetes medication History, N(%)

356(3.21)

474(4.51)

296(5.22)

< 0.001

FVC, Mean ± SD

3.50 ± 0.85

3.46 ± 0.83

3.41 ± 0.83

< 0.001

FEV₁, Mean ± SD

2.96 ± 0.71

2.95 ± 0.71

2.91 ± 0.73

< 0.001

FVC%, Mean ± SD

99.8 ± 15.3

100 ± 15.1

101 ± 16.7

< 0.001

FEV₁%, Mean ± SD

93.1 ± 14.5

95.3 ± 13.7

98.3 ± 22.9

< 0.001

FEV₁/FVC, Mean ± SD

85.0 ± 8.46

85.4 ± 8.64

85.8 ± 8.35

< 0.001