Table 3 Means and changes by year of lung function parameter observed and predicted from GLI and their differences for asymptomatic subjects, compared with t -test for paired data

FEV ₁ (ml)

Observed

1107.4

2435.9

180.4

Predicted

1123.2

2497.5

188.3

δ

−15.8

NS

−61.6

*

−7.9

*

95% CI of δ

(−32.8 - +5.6)

(−103.4 --19.8)

Z-score 50 _tile

−0.138

−0.203

Z-score 5 _tile

−1.583

−1.548

lln

879.5

2017.8

FVC (ml)

Observed

1120.7

2824.1

233.4

Predicted

1216.0

2876.4

227.8

δ

−95.2

**

−52.3

**

5.6

**

95% CI of δ

(−116.2 - -74.3)

(−91.9 - -12.7)

Z-score 50 _tile

−0.645

−0.113

Z-score 5 _tile

−1.954

−1.468

lln

943.9

2329.9

FEV ₁ /FVC (%)

Observed

96.6

85.5

−1.57

Predicted

92.9

87.1

−0.8

δ

3.7

**

−2.4

**

−0.77

**

95% CI of δ

(+3.0 - +4.3)

(−2.4 - -0.8)

Z-score 50 _tile

0.961

−0.207

Z-score 5 _tile

−0.905

−1.664

lln

81.6

76.3

FEF _25–75 (ml/s)

Observed

1621.3

2766.9

152.8

Predicted

1602.6

2955.8

185.2

δ

18.7

NS

−269.6

**

−32.3

**

95% CI of δ

(−25.0 - +62.3)

(−269.6 - -108.2)

Z-score 50 _tile

0.045

−0.306

Z-score 5 _tile

−1.357

−1.912

lln

967.0

1954.3