Table 4.

Meta-analysis of postbronchodilator FEV₁,/FVC ratio including interactions for age and atopy and age and diagnosis

	Model 1						Model 2
Variables	Estimates	Confidence (95%)	limits	P value*	I 2	P value (heterogeneity)†	Estimates	Confidence (95%)	limits	P value*	I 2	P value (heterogeneity)†
Age/year from 20 (years)	−0.250	−0.291	−0.209	<0.001	37.8	0.058	−0.241	−0.274	−0.207	<0.001	39.3	0.049
Sex
Female	–	–	–	–	–	–	–	–	–	–	–	–
Male	0.062	−0.806	0.929	0.889	4.2	0.405	−0.192	−1.024	0.640	0.651	0.0	0.721
Height/m	−0.097	−0.145	−0.050	<0.001	15.4	0.273	−0.088	−0.134	−0.042	<0.001	12.5	0.307
Cases grouping
Controls (ref)	–	–	–	–	–	–	–	–	–	–	–	–
Asthmatic	−4.001	−5.018	−2.984	<0.001	27.3	0.143	−0.128	−1.508	1.252	0.856	0.0	0.948
Sinusitis	−0.307	−1.229	0.614	0.513	4.2	0.406	−1.231	−3.980	1.518	0.380	55.4	0.004
Both Asthma & Sinusitis	−2.942	−4.070	−1.815	<0.001	10.1	0.335	−3.413	−9.937	3.111	0.305	87.4	<0.001
Age*case interaction
Controls (ref)							–	–	–	–	–	–
Asthmatic*Age							−0.135	−0.186	−0.084	<0.001	0.0	0.658
Sinusitis*Age							0.030	−0.063	0.122	0.529	52.8	0.006
Both Asthma & Sinusitis*Age							−0.003	−0.233	0.228	0.982	85.5	<0.001
Smoking (per pack year)	−0.086	−0.123	−0.049	<0.001	50.5	0.009	−0.084	−0.120	−0.048	<0.001	42.9	0.031
Smoking status
Never (ref)	–	–	–	–	–	–	–	–	–	–	–	–
Former	−0.439	−1.710	0.832	0.498	60.0	0.001	−0.457	−1.731	0.818	0.482	59.8	0.001
Current	−1.971	−2.971	−0.970	<0.001	0.0	0.518	−2.235	−3.238	−1.231	<0.001	0.4	0.449
Atopy
No Atopy (ref)	–	–	–	–	–	–
Atopy	0.996	−0.326	2.318	0.140	6.1	0.385
Atopy*Age	−0.034	−0.083	0.014	0.166	17.8	0.260

Atopy was considered positive if ≥3 mm reaction size to any of the allergens.

FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity.

^*Effect Estimate.

^†Heterogeneity of effects between centers.