Outcomes Associated with Lung Function and Symptoms
Monaghan spirometer that was replaced with a dry wedge
spirometer by examination 3 or to other issues (38). To ad-
just for this increase, we reduced the individual FEV1 mea-
surements for 1981 by a fixed value of 289 ml for males and
201 ml for females to align the 1981 values with the 1976– 78
and 1982– 83 values. The fixed values represent the average
difference in FEV1 values from examination 1 to 2 (for 1982
only), minus 30 ml to correct for annual loss from 1981 to
1982. Models excluding the 1981 values were conducted for
a sensitivity analysis regarding this adjustment.
RESULTS
Three sub-cohorts (males, females, and never-smokers) used
in the Cox models are described in Table 1. The table shows
the duration of follow-up for morbidity and mortality (15–20
years), the mean and quartile values for FEV1/height2 (level
of lung function) and the 2 types of slopes (lung function decline), and the frequency of symptoms and asthma.
For never-smokers, we presented gender-specific quartiles
Table 1. Characteristics of the sub-cohorts for Cox proportional hazards model analysis using data for lung function level and decline
Males Females Never-smokers
Data for lung function level (Examination 2)
5,494
56.1
44.8
12.6
6,771
56.7
55.2
12.1
2,555
56.4
20.8
13.8
15.4
16.9
17.1
174
2.82
2.57
2.07
2.56
3.08
172
872
543
629
1,352
3,510
6.9
7.9
8.1
7
0.91
0.75
17.3
19.3
19.5
161
2.05
2.17
1.78
2.17
2.58
218
722
728
1,926
1,244
3,592
6.0
7.0
7.2
6
0.63
0.60
5.7
6.7
7.0
9
0.85
0.67
3.1
15.9
9.9
11.5
24.6
63.9
3.2
10.7
10.8
28.5
18.4
53.1
18.1
20.0
20.3
164
2.39
2.42
2.43; 1.87‡
2.92; 2.23‡
3.41; 2.65‡
59
148
159
629; 1,926‡
2.3
5.8
6.2
24.6; 75.4‡
Data for lung function decline (Examination 1 to 2)§
Subjects(n,∗%) 4,253 43.9 5,426
Baseline age (mean, SD) 52.5 11.4 52.7
Follow-up, years (mean, SD)
COPD morbidity 15.2 6.9
COPD or CHD mortality 16.7 7.9
All-cause mortality 16.9 8.1
Baseline FEV1, l (mean, SD) 3.09 0.82
Baseline FEV1/height2 × mean height2, l (mean, SD) 2.83 0.67
Slope FEV1, ml/yr† (mean, SD) – 62 94
25th percentile – 118
Median – 60
75th percentile 0
Slope FEV1/baseline FEV1,%/yr (mean, SD) –2.0 3.4
25th percentile –4.1
Median –2.2
75th percentile 0.0
FEV1 below LNL† (n,%) 743 17.4
FEV1 decline of 90 ml/yr or more (n,%) 1,717 40.4
Asthma (n,%) 125 2.9
Chronic bronchitis (n,%) 665 15.6
Shortness of breath (n,%) 401 9.4
∗ A total of 12,265 subjects at examination 2 and 9,679 subjects at both examinations 1 and 2.
†SD (standard deviation), cm (centimeters), l (liters), ml/yr (milliliters/year), and LNL (Longitudinal Normal Limit).
‡Males; females.
§Includes subjects with approximately 5 years between spirometry tests.
56.1
10.8
1,822
52.8
18.8
12.2
17.3
19.3
19.6
2.25
2.40
–45
– 95
– 57
0
–1.9
–4.1
–2.2
0.0
1,016
1,444
168
558
550
6.0
6.9
7.1
0.55
0.53
71
5.6
6.7
6.9
0.79
0.62
80
3.4
18.2
20.1
20.4
2.56
2.62
–43
– 114; – 94‡
– 57; –40‡
19; 0‡
–1.5
–3.2; –3.8‡
–1.5; –2.0‡
0.4; 0.0‡
346
505
40
96
104
3.4
18.7
26.6
3.1
10.3
10.1
19.0
27.7
2.2
5.3
5.7
