Adjusted odds ratios (aORs) (95% CI) for incident asthma at 11 or 14 years according to quartiles of intakes of preformed vitamin A and β-carotene equivalent, stratified by BCMO1 (β-carotene 15,15′-monooxygenase 1) genotypes
| Quartiles of vitamin A intake | ptrend-value# | pinteraction-value | ||||
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | |||
| Preformed vitamin A | ||||||
| Upstream BCMO1: rs6564851 | ||||||
| TT¶: cases/non-cases | 16/189 | 14/205 | 17/191 | 17/188 | ||
| aOR (95% CI) | 1.00 | 0.73 (0.32–1.66) | 1.01 (0.44–2.30) | 0.89 (0.35–2.28) | 0.99 | |
| TG: cases/non-cases | 41/389 | 36/421 | 40/397 | 45/378 | ||
| aOR (95% CI) | 1.00 | 0.87 (0.54–1.43) | 0.96 (0.58–1.58) | 1.12 (0.63–1.98) | 0.61 | 0.92 |
| GG: cases/non-cases | 26/221 | 16/240 | 25/249 | 20/250 | ||
| aOR (95% CI) | 1.00 | 0.43 (0.21–0.85) | 0.59 (0.31–1.13) | 0.34 (0.15–0.77) | 0.03 | 0.48 |
| BCMO1 coding region: rs7501331 | ||||||
| CC¶: cases/non-cases | 53/463 | 34/512 | 53/466 | 45/515 | ||
| aOR (95% CI) | 1.00 | 0.49 (0.31–0.78) | 0.80 (0.51–1.25) | 0.47 (0.28–0.81) | 0.04 | |
| CT: cases/non-cases | 25/285 | 26/303 | 25/324 | 29/255 | ||
| aOR (95% CI) | 1.00 | 1.08 (0.59–2.00) | 0.94 (0.49–1.81) | 1.31 (0.63–2.73) | 0.51 | 0.23 |
| TT: cases/non-cases | 5/51 | 6/51 | <5/47 | 8/46 | ||
| aOR (95% CI) | 1.00 | 0.86 (0.16–4.73) | 0.93 (0.16–5.27) | 6.85 (0.91–51.7) | 0.06 | 0.41 |
| β-carotene equivalent | ||||||
| Upstream BCMO1: rs6564851 | ||||||
| TT¶: cases/non-cases | 7/192 | 13/215 | 15/190 | 29/176 | ||
| aOR (95% CI) | 1.00 | 2.00 (0.75–5.31) | 2.70 (1.01–7.19) | 5.20 (2.04–13.27) | <0.001 | |
| TG: cases/non-cases | 45/375 | 34/404 | 37/403 | 46/403 | ||
| aOR (95% CI) | 1.00 | 0.72 (0.45–1.17) | 0.77 (0.47–1.27) | 0.93 (0.57–1.51) | 0.93 | 0.001 |
| GG: cases/non-cases | 22/228 | 16/232 | 33/252 | 16/248 | ||
| aOR (95% CI) | 1.00 | 0.61 (0.31–1.23) | 1.08 (0.58–1.99) | 0.51 (0.24–1.08) | 0.10 | <0.001 |
| BCMO1 coding region: rs12934922 | ||||||
| AA¶: cases/non-cases | 25/244 | 28/257 | 24/279 | 24/272 | ||
| aOR (95% CI) | 1.00 | 1.14 (0.63–2.05) | 0.83 (0.44–1.59) | 0.91 (0.47–1.76) | 0.71 | |
| AT: cases/non-cases | 36/394 | 27/422 | 40/388 | 38/404 | ||
| aOR (95% CI) | 1.00 | 0.68 (0.40–1.15) | 1.03 (0.62–1.72) | 0.90 (0.53–1.53) | 0.89 | 0.43 |
| TT: cases/non-cases | 13/157 | 8/172 | 21/178 | 29/151 | ||
| aOR (95% CI) | 1.00 | 0.62 (0.24–1.58) | 1.67 (0.76–3.67) | 2.52 (1.15–5.52) | 0.003 | 0.005 |
Data for case/non-cases are presented as n/n. Adjusted odds ratio (multivariable model) for 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. #: linear trend was tested by treating the median values of quartiles as a continuous variable; ¶: homozygous alleles linked to a more efficient conversion of carotene pro-vitamin A.