TABLE 3

Results of the multivariable model analysis

Interaction effect#Main effect
Degrees of freedomp-valueDifference±seDegrees of freedomp-value
Males versus females4<0.00012.32±0.541<0.0001
Country-status8<0.00012<0.0001
 Middle versus low4<0.00019.61±0.761<0.0001
 High versus low4<0.00018.15±0.731<0.0001
 High versus middle4<0.0001−1.47±0.601<0.0001
Neonatal screening120.00553<0.0001
 Not done versus result positive40.0024−3.93±0.651<0.0001
 Not done versus result negative40.0931−5.41±1.181<0.0001
 Not done versus result unknown40.0593−3.07±0.721<0.0001
 Result positive versus result negative40.5407−1.48±1.1910.2925
 Result positive versus result unknown40.48190.86±0.7610.1381
 Result negative versus result unknown40.21392.34±1.2110.1111
No ileus meconium versus ileus meconium40.75550.54±0.6910.2640
Sweat values120.09373<0.0001
 Q1 versus Q240.45810.95±0.6710.0339
 Q1 versus Q340.18702.14±0.671<0.0001
 Q1 versus Q440.07922.24±0.671<0.0001
 Q2 versus Q340.11431.19±0.6410.0034
 Q2 versus Q440.31221.29±0.6310.0013
 Q3 versus Q440.11790.11±0.6310.7922
Mutation20<0.00015<0.0001
 Both class I/II versus both F508del40.5984−0.18±0.6110.6199
 Both class I/II versus at least one class III4<0.0001−2.44±0.9110.0029
 Both class I/II versus at least one class IV4<0.0001−6.05±0.821<0.0001
 Both class I/II versus at least one class V4<0.0001−5.10±0.851<0.0001
 Both class I/II versus one of class I/II, other unknown4<0.0001−3.07±0.681<0.0001
 Both F508del versus at least one class III4<0.0001−2.25±0.8910.0045
 Both F508del versus at least one class IV4<0.0001−5.87±0.801<0.0001
 Both F508del versus at least one class V4<0.0001−4.92±0.841<0.0001
 Both F508del versus one of class I/II, other unknown4<0.0001-2.89±0.661<0.0001
 At least one class III versus at least one class IV40.1260-3.61±0.9810.0002
 At least one class III versus at least one class V40.0077-2.66±1.0010.0080
 At least one class III versus one of class I/II, other unknown40.0002-0.64±0.9210.4520
 At least one class IV versus at least one class V40.16250.95±0.9210.2577
 At least one class IV versus one of class I/II, other unknown40.00452.98±0.821<0.0001
 At least one class V versus one of class I/II, other unknown40.90292.03±0.8510.0053
Age at diagnosis11+<0.00013<0.0001
 <1 year versus 1–10 years40.0004−0.99±0.6110.0089
 <1 year versus 11–18 years4<0.0001−1.82±0.9210.0331
 <1 year versus >18 years4<0.0001−11.3±1.111<0.0001
 1–10 years versus 11–18 years40.0011−0.84±0.9210.3257
 1–10 years versus >18 years4<0.0001−10.3±1.111<0.0001
 11–18 years versus >18 years40.1509−9.50±1.191<0.0001

p-values and estimates for the main effects and p-values for the interaction effects are given. To interpret the effect of each factor on the decline of forced expiratory volume in 1 s (FEV1), refer to the relevant figure. Q: quartile. #: i.e. does the rate of change depend on gender, age at diagnosis, etc.; : i.e. does the mean FEV1 (averaged over the age range) depends on gender, age at diagnosis, etc.; +: the interaction effect of age at diagnosis contained 11 instead of 12 degrees of freedom, due to overparametrisation of the model.