Effect of deficiency of α1-antichymotrypsin and the three different −15 α1-antichymotrypsin signal peptide genotypes: Ala/Ala, Thr/Thr and Ala/Thr on FEV1 % and the Northern chest radiography score
| Outcome measure | Normal ACT | ACT deficiency | p value |
Alanine (GG) | Threonine (AA) |
Ala/Thr (GA) | p value |
| FEV1(%) | |||||||
| Observed mean (SD) | 52.5 (23.9) | 80.0 (16.7) | 59.5 (25.1) | 57.1 (21.7) | 56.1 (21.6) | ||
| Adjusted mean (95% CI)2-a | 53.2 | 69.9 | 0.04 | 65.0 | 44.6 | 51.6 | 0.004 |
| (49.9 to 56.4) | (55.3 to 84.5) | (58.8 to 71.2) | (33.3 to 56.0) | (44.4 to 58.7) | |||
| Radiography score | |||||||
| Observed mean (SD) | 9.5 (3.6) | 6.4 (2.5) | 8.9 (3.5) | 10.7 (3.6) | 8.8 (3.6) | ||
| Adjusted mean (95% CI)2-b | 9.7 | 7.2 | 0.03 | 8.1 | 12.1 | 9.4 | 0.004 |
| (9.1 to 10.2) | (4.9 to 9.5) | (7.0 to 9.1) | (10.1 to 14.1) | (8.2 to 10.7) | |||
Differences between the groups were assessed by analysis of covariance.
↵2-a Covariates in the final model for FEV1 and α1-antichymotrypsin were age, body mass index, colonisation with P aeruginosa, and pancreatic status. For FEV1 and the signal peptide genotypes the covariates were age, body mass index, and α1-antichymotrypsin.
↵2-b Covariates in the final model for radiographic score and α1-antichymotrypsin were age, body mass index, and colonisation with P aeruginosa. For the radiographic score and the signal peptide genotypes the covariates were age, body mass index, and plasma levels of α1-antichymotrypsin.