Maternal intake of vitamins A, E and K in pregnancy and child allergic disease: a longitudinal study from the Danish National Birth Cohort

Fat-soluble vitamins A, E and K have been shown to play roles in immunity and inflammation, but studies on child allergic disease have been few and inconsistent. The aim of the present study was to examine the relationship between maternal intake of vitamins A, E and K in mid-pregnancy and child asthma and allergic rhinitis. We used data on 44 594 mother–child pairs from the Danish National Birth Cohort. Maternal intake of fat-soluble vitamins was calculated based on the information from a validated FFQ completed in mid-pregnancy. At 18 months, interviews with the mothers were conducted to evaluate doctor-diagnosed child asthma. At age 7 years, we assessed child asthma and allergic rhinitis using questions from the International Study of Asthma and Allergies in Childhood questionnaire and by national registries on hospital contacts and medication use. Current asthma was defined as asthma diagnosis and wheeze in the past 12 months by maternal report. We calculated multivariable risk ratios and 95 % CI by comparing the highest v. lowest quintile (Q) of maternal vitamin A, E and K intake in relation to child allergic disease outcomes. Maternal total vitamin K intake was directly associated with ever admitted asthma (Q5 v. Q1: 1·23, 95 % CI 1·01, 1·50) and current asthma at 7 years (Q5 v. Q1: 1·30, 95 % CI 0·99, 1·70). Weak inverse associations were present for maternal vitamin A and E intake during pregnancy with child allergic rhinitis. Maternal vitamin K intake during pregnancy may increase the risk of child asthma, and should be explored further on a mechanistic level. Conversely, maternal vitamin A and E intake may protect against child allergic rhinitis.