Abstract
BackgroundLongitudinal epidemiological data are scarce on the relationship between dietary intake of vitamin A and respiratory outcomes in childhood. We investigated whether a higher intake of preformed vitamin A or pro-vitamin β-carotene in mid-childhood is associated with higher lung function and with asthma risk in adolescence.MethodsIn the Avon Longitudinal Study of Parents and Children, dietary intakes of preformed vitamin A and β-carotene equivalents were estimated by food frequency questionnaire at 7 years of age. Post-bronchodilator forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and forced expiratory flow at 25–75% of FVC (FEF25–75%) were measured at 15.5 years and transformed to z-scores. Incident asthma was defined by new cases of doctor-diagnosed asthma at age 11 or 14 years.ResultsIn multivariable adjusted models, a higher intake of preformed vitamin A was associated with higher lung function and a lower risk of incident asthma: comparing top versus bottom quartiles of intake, regression coefficients for FEV1 and FEF25–75% were 0.21 (95% CI 0.05–0.38; ptrend=0.008) and 0.18 (95% CI 0.03–0.32; ptrend=0.02), respectively; odds ratios for FEV1/FVC below the lower limit of normal and incident asthma were 0.49 (95% CI 0.27–0.90; ptrend=0.04) and 0.68 (95% CI 0.47–0.99; ptrend=0.07), respectively. In contrast, there was no evidence for association with β-carotene. We also found some evidence for modification of the associations between preformed vitamin A intake and lung function by BCMO1, NCOR2 and SCGB1A1 gene polymorphisms.ConclusionA higher intake of preformed vitamin A, but not β-carotene, in mid-childhood is associated with higher subsequent lung function and lower risk of fixed airflow limitation and incident asthma.
Highlights
Vitamin A is a versatile vitamin involved in multiple biological processes including lung development through regulating the expression of several hundred genes [1]
Genotyping and SNPs selection We considered single-nucleotide polymorphisms (SNPs) that were associated with bioavailability or metabolism of vitamin A in the literature and selected those that could plausibly interact with dietary vitamin A intake and/or have been associated with lung function
We found evidence of effect modification by two of the SNPs in the coding region of BCMO1: in carriers of the T allele of rs7501331, but not in those homozygous for the C allele, higher intake of preformed vitamin A was associated with higher forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) (P for interaction 0.03 and 0.01, respectively), whereas in carriers of the A allele of rs12934922 higher intake of β-carotene was associated with higher FEV1 (P for interaction 0.01)
Summary
Vitamin A is a versatile vitamin involved in multiple biological processes including lung development through regulating the expression of several hundred genes [1]. Follow-up of a trial in a vitamin A deficient area showed that vitamin A supplementation in early life (peri-pregnancy) improved offspring lung function [8], with no impact on the subsequent risk of asthma [9]. In a birth cohort study in Norway, excess vitamin A intake in pregnancy was associated with a higher risk of childhood asthma [10], whilst some case-control studies in children have suggested an inverse association between dietary or serum vitamin A and asthma [11]. An inverse association between serum retinol and subsequent airway obstruction was reported [12], whereas more recently a positive association was found between vitamin A intake and asthma [13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
