Table 1 Characteristics of the subjects by age group

Age (years)

54.6 ± 9.1

44.8 ± 2.9

54.7 ± 2.9

63.5 ± 2.9

74.2 ± 3.8

BMI (kg/m²)

23.7 ± 2.9

24.0 ± 3.1

23.8 ± 2.8

23.4 ± 2.6

23.0 ± 2.7

FEV₁ % predicted

94.2 ± 11.2

94.2 ± 9.4

94.1 ± 10.7

94.3 ± 12.8

94.8 ± 16.2

FEV₁/FVC (%)

78.5 ± 6.4

80.4 ± 5.4

78.7 ± 6.0

76.5 ± 6.7

74.2 ± 8.3

Creatinine (mg/dL)

0.12 ± 0.37

0.11 ± 0.31

0.11 ± 0.33

0.14 ± 0.49

0.14 ± 0.39

Estimated GFR (mL/min/1.73 m²)

74.3 ± 13.0

78.6 ± 12.0

74.4 ± 12.5

70.3 ± 12.6

65.6 ± 13.6

CRP (mg/L)

0.12 ± 0.37

0.11 ± 0.31

0.11 ± 0.33

0.14 ± 0.49

0.14 ± 0.39

Hyper-LDL-cholesterolemia (%)

32.5

31.4

33.1

32.6

33.2

Hypertension (%)

31.2

19.1

32.3

40.8

52.5

Diabetes (%)

9.9

5.2

11.0

14.2

12.3

Medication

 Treatment for cholesterolemia (%)

8.2

4.2

8.5

11.3

16.2

 Treatment for hypertension (%)

19.2

7.5

19.9

29.0

41.1

 Treatment for diabetes (%)

5.2

1.9

5.5

8.2

9.1

Chronic kidney disease (%)

10.6

3.1

9.5

17.4

31.5

Airflow obstruction (%)

7.9

3.1

6.4

13.6

22.0

Lung function status (%)

 Normal lung function

92.1

96.9

93.6

86.4

78.0

 GOLD stage I

3.9

1.5

3.0

7.0

11.1

 GOLD stage II–IV

4.0

1.6

3.4

6.6

10.9

Smoking history (%)

 Never smokers

31.8

32.1

27.4

36.1

42.4

 Former smokers

38.0

27.7

40.5

46.3

47.1

 Current smokers

30.2

40.2

32.1

17.7

10.5

Pack-years^a

18.7 ± 20.0

14.4 ± 14.6

20.8 ± 20.2

21.2 ± 24.1

18.8 ± 23.1

Alcohol intake (%)

 Non-drinkers

23.8

25.5

22.0

22.9

29.1

 1–2 days/week

13.2

16.0

11.9

11.6

12.1

 3–4 days/week

11.2

11.7

11.6

9.9

10.6

 5–6 days/week

12.9

12.5

12.5

13.8

14.5

 Everyday drinkers

38.9

34.3

42.0

41.8

33.8

Regular physical activity^b (%)

36.1

24.3

32.4

52.0

66.2