TABLE 4

Results for the association between season-adjusted 25-hydroxyvitamin D concentrations per 10 nmol·L⁻¹ increase and lung function measurements post-bronchodilation

	Model 1^#			Model 2^¶
	β	95% CI	p-value	β	95% CI	p-value

FEV₁	0.014	0.007–0.020	<0.001	0.011	0.004–0.018	0.004
FVC	0.023	0.015–0.030	<0.001	0.019	0.011–0.027	<0.001
FEV₁/FVC	−0.148	−0.235– −0.061	0.001	−0.139	−0.236– −0.042	0.005
PEF	0.016	−0.001–0.033	0.060	0.016	−0.003–0.035	0.091
FEF₂₅	0.004	−0.013–0.021	0.617	0.011	−0.008–0.030	0.259
FEF₅₀	0.007	−0.008–0.022	0.380	0.005	−0.012–0.022	0.578
FEF₇₅	−0.005	−0.017–0.007	0.449	−0.010	−0.023–0.004	0.168
FEF_25–75	0.002	−0.011–0.016	0.723	−0.001	−0.016–0.015	0.934

z-score FEV₁ GLI	0.030	0.016–0.045	<0.001	0.025	0.008–0.041	0.003
z-score FVC GLI	0.044	0.030–0.058	<0.001	0.038	0.022–0.053	<0.001
z-score FEV₁/FVC GLI	−0.025	−0.040– −0.010	0.001	−0.024	−0.041– −0.007	0.005
z-score FEF₇₅ GLI	−0.006	−0.021–0.009	0.462	−0.011	−0.028–0.006	0.199
z-score FEF_25–75 GLI	0.002	−0.012–0.017	0.756	0.000	−0.017–0.016	0.956

Values presented in bold are statistically significant at p<0.05. FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; PEF: peak expiratory flow; FEF₂₅, FEF₅₀, FEF₇₅: forced expiratory flow rates at 25, 50 and 75% of exhaled FVC; FEF_25–75: mean flow rate between 25 and 75% of FVC; GLI: z-scores according to the Global Lung function Initiative [23]. ^#: adjusted for sex, study and study region, age, height and weight at lung function testing. ^¶: adjusted for all variables in Model 1 plus birthweight, time spent in front of a TV/PC, current asthma and/or positive bronchodilation response, exposure to tobacco smoke at home up to age 4 years, parental education, parental atopy, maternal smoking during pregnancy and breastfeeding.