Dietary patterns, lung function and asthma in childhood: a longitudinal study

Table 3 Linear regression coefficients (95% confidence interval) for post-bronchodilator lung function measures (z scores) at 15.5 years according to quartiles of the ‘health-conscious’ dietary pattern score at 7 years, stratified by rs713041 polymorphism genotypes of GPX4 gene

	Quartiles of dietary pattern score				P for	P for
	Q1	Q2	Q3	Q4	trend^a	interaction
‘Health-conscious’ dietary pattern
FEV₁
Genotype CC	0.00	0.12 (− 0.16, 0.40)	− 0.03 (− 0.32, 0.25)	− 0.04 (− 0.34, 0.26)	0.54
Genotype CT/TT	0.00	0.10 (− 0.09, 0.30)	0.13 (− 0.07, 0.33)	0.25 (0.04, 0.46)	0.02	0.009
FVC
Genotype CC	0.00	0.12 (− 0.15, 0.38)	0.02 (− 0.26, 0.29)	0.05 (− 0.24, 0.33)	0.97
Genotype CT/TT	0.00	0.12 (− 0.06, 0.31)	0.09 (− 0.10, 0.28)	0.26 (0.06, 0.47)	0.02	0.03
FEV₁/FVC ratio
Genotype CC	0.00	0.05 (− 0.18, 0.28)	− 0.05 (− 0.29, 0.19)	− 0.15 (− 0.40, 0.11)	0.15
Genotype CT/TT	0.00	− 0.06 (− 0.23, 0.11)	0.05 (− 0.12, 0.21)	− 0.03 (− 0.21, 0.14)	0.92	0.38
FEF_25–75
Genotype CC	0.00	0.05 (− 0.18, 0.28)	− 0.09 (− 0.33, 0.15)	− 0.21 (− 0.46, 0.04)	0.04
Genotype CT/TT	0.00	0.14 (− 0.03, 0.31)	0.12 (− 0.05, 0.29)	0.21 (0.02, 0.39)	0.05	0.001

Multivariable model: sex, total energy intake, maternal education, housing tenure at birth, financial difficulty during pregnancy, maternal ethnicity, index of multiple deprivation, rural living location, maternal and paternal history of atopic disease, older sibling, younger sibling, breastfeeding, maternal smoking, vigorous physical activity, history of food allergy, and season when the FFQ was completed
FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; FEF_25–75: forced expiratory flow at 25–75% of FVC; GPX4: glutathione peroxidase 4
^aLinear trend was tested by treating the median values of quartiles as a continuous variable
In CC and CT/TT groups of GPX4-rs713041, sample sizes were 747 and 1598 for FEV₁, and 778 and 1679 for both FVC and FEF_25-75, respectively