TABLE 3.
Linear regression coefficients (95% CI) for post-bronchodilator lung function measures (z-scores) according to quartiles of intakes of preformed vitamin A and β-carotene equivalent, stratified by SCGB1A1 (club cell secretory protein CC16)# genotype (rs3741240)
| Quartiles of vitamin A intake | ptrend-value ¶ | pinteraction-value | ||||
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | |||
| Preformed vitamin A | ||||||
| FEV1 | ||||||
| Genotype GG | 0.00 | −0.12 (−0.37–0.12) | 0.01 (−0.24–0.27) | 0.27 (−0.01–0.56) | 0.02 | |
| Genotype GA | 0.00 | −0.02 (−0.25–0.20) | −0.05 (−0.28–0.19) | 0.13 (−0.14–0.39) | 0.33 | 0.35 |
| Genotype AA | 0.00 | 0.10 (−0.30–0.50) | 0.02 (−0.39–0.43) | −0.09 (−0.57–0.38) | 0.65 | 0.07 |
| FVC | ||||||
| Genotype GG | 0.00 | −0.12 (−0.35–0.12) | −0.04 (−0.28–0.20) | 0.11 (−0.16–0.39) | 0.24 | |
| Genotype GA | 0.00 | 0.02 (−0.19–0.23) | −0.02 (−0.24–0.20) | 0.11 (−0.15–0.36) | 0.43 | 0.88 |
| Genotype AA | 0.00 | 0.12 (−0.27–0.52) | 0.11 (−0.29–0.51) | 0.05 (−0.42–0.52) | 0.85 | 0.42 |
| FEV1/FVC | ||||||
| Genotype GG | 0.00 | 0.07 (−0.13–0.27) | 0.19 (−0.02–0.40) | 0.32 (0.08–0.55) | 0.004 | |
| Genotype GA | 0.00 | −0.05 (−0.25–0.15) | 0.02 (−0.18–0.23) | 0.00 (−0.24–0.24) | 0.86 | 0.15 |
| Genotype AA | 0.00 | −0.03 (−0.36–0.30) | −0.24 (−0.58–0.09) | −0.29 (−0.68–0.10) | 0.09 | 0.02 |
| FEF25–75% | ||||||
| Genotype GG | 0.00 | −0.02 (−0.23–0.19) | 0.08 (−0.13–0.30) | 0.31 (0.07–0.55) | 0.004 | |
| Genotype GA | 0.00 | −0.01 (−0.20–0.18) | −0.03 (−0.23–0.17) | 0.10 (−0.13–0.33) | 0.40 | 0.35 |
| Genotype AA | 0.00 | 0.13 (−0.21–0.48) | 0.08 (−0.27–0.43) | −0.27 (−0.68–0.13) | 0.18 | 0.01 |
| β- carotene equivalent | ||||||
| FEV1 | ||||||
| Genotype GG | 0.00 | 0.05 (−0.18–0.29) | 0.12 (−0.13–0.36) | 0.10 (−0.15–0.35) | 0.48 | |
| Genotype GA | 0.00 | 0.04 (−0.17–0.26) | 0.21 (−0.02–0.43) | −0.04 (−0.27–0.19) | 0.52 | 0.36 |
| Genotype AA | 0.00 | −0.04 (−0.45–0.37) | −0.06 (−0.50–0.39) | 0.15 (−0.31–0.61) | 0.36 | 0.88 |
| FVC | ||||||
| Genotype GG | 0.00 | −0.10 (−0.32–0.13) | 0.06 (−0.18–0.29) | −0.02 (−0.26–0.22) | 0.99 | |
| Genotype GA | 0.00 | 0.07 (−0.13–0.28) | 0.14 (−0.07–0.36) | 0.05 (−0.18–0.27) | 0.87 | 0.93 |
| Genotype AA | 0.00 | −0.03 (−0.43–0.37) | −0.07 (−0.50–0.36) | 0.05 (−0.40–0.50) | 0.71 | 0.94 |
| FEV1/FVC | ||||||
| Genotype GG | 0.00 | 0.18 (−0.02–0.37) | 0.04 (−0.16–0.24) | 0.07 (−0.14–0.27) | 0.80 | |
| Genotype GA | 0.00 | 0.02 (−0.18–0.21) | 0.08 (−0.12–0.28) | −0.16 (−0.37–0.05) | 0.06 | 0.21 |
| Genotype AA | 0.00 | −0.06 (−0.39–0.28) | −0.00 (−0.37–0.36) | 0.09 (−0.29–0.47) | 0.46 | 0.55 |
| FEF25–75% | ||||||
| Genotype GG | 0.00 | 0.16 (−0.04–0.36) | 0.10 (−0.11–0.30) | 0.15 (−0.06–0.37) | 0.25 | |
| Genotype GA | 0.00 | 0.03 (−0.15–0.22) | 0.17 (−0.03–0.36) | −0.01 (−0.21–0.19) | 0.69 | 0.43 |
| Genotype AA | 0.00 | −0.09 (−0.44–0.27) | −0.03 (−0.40–0.35) | 0.03 (−0.37–0.43) | 0.69 | 0.66 |
FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; FEF25–75%: forced expiratory flow at 25–75% of FVC. Multivariable model: sex, total energy intake, maternal education, housing tenure at birth, financial difficulty during pregnancy, maternal ethnicity, maternal history of atopic disease, paternal history of atopic disease, maternal smoking, older sibling, younger sibling, supplement use and season when the food frequency questionnaire was completed. #: in GG, GA and AA groups, sample sizes were 1074, 1133 and 348 for FEV1, and 1126, 1183 and 360 for both FVC and FEF25–75%, respectively; ¶: linear trend was tested by treating the median values of quartiles as a continuous variable.