Table 2– Crude associations between potential determinants and the baseline lung function

	log₁₀R_rs₆			log₁₀AX
Continuous variables	B	se	p-value	B	se	p-value
Current height cm	−0.005	0.001	<0.001	−0.013	0.003	<0.001
Current weight kg	−0.004	0.002	0.037	−0.014	0.006	0.017
Gestational age weeks	−0.004	0.003	0.119	−0.016	0.008	0.049
Birth weight kg	−0.024	0.009	0.007	−0.064	0.026	0.012
Categorical variables	Mean	se	p-value^#	Mean	se	p-value^#
Parental asthma
No	0.997	0.005	Ref.	1.259	0.014	Ref.
Mother	1.025	0.020	0.100	1.356	0.055	0.054
Father	1.003	0.017	0.773	1.247	0.049	0.833
Both parents	1.108	0.016	0.127	1.455	0.050	0.357
Postnatal ETS
Never	1.005	0.005	Ref.	1.268	0.016	Ref.
First in first year	1.018	0.018	0.403	1.341	0.048	0.113
First after first year	0.970	0.014	0.055	1.236	0.040	0.541
LRTI
Never	0.984	0.008	Ref.	1.223	0.023	Ref.
First in first year	1.002	0.028	0.585	1.365	0.073	0.122
First after first year	1.019	0.009	0.003	1.319	0.025	0.005
Number of LRTIs
0	0.984	0.008	Ref.	1.223	0.023	Ref.
1	1.021	0.013	0.016	1.308	0.039	0.051
>1	1.024	0.015	0.013	1.345	0.041	0.008
Timing of wheeze
Never	0.982	0.008	Ref.	1.211	0.023	Ref.
Early/transient	1.011	0.009	0.022	1.324	0.027	0.002
Late onset	1.116	0.057	0.001	1.484	0.154	0.020
Persistent	1.048	0.014	<0.001	1.399	0.045	<0.001
Number of wheeze episodes
0	0.982	0.008	Ref.	1.211	0.023	Ref.
1	1.005	0.016	0.155	1.300	0.040	0.067
>1	1.045	0.010	<0.001	1.407	0.031	<0.001
Inhalant atopy
Never	1.004	0.005	Ref.	1.276	0.016	Ref.
First at 1 year	1.068	0.022	0.004	1.520	0.057	<0.001
First at 4 years	0.989	0.012	0.239	1.233	0.032	0.272
Number of inhalant allergens
0	1.004	0.005	Ref.	1.276	0.016	Ref.
1	0.987	0.014	0.244	1.251	0.038	0.564
>1	1.040	0.017	0.043	1.386	0.051	0.035

Numbers in bold indicate p<0.05. R_rs₆: respiratory resistance at 6 Hz; AX: area under the reactance curve; B: unstandardised regression coefficient; ETS: environmental tobacco smoke; LRTI: lower respiratory tract infection. ^#: least-significant difference post hoc test.