Neonatal vitamin D status and childhood peanut allergy: a pilot study.
Although a number of factors have been proposed to explain the increase in food allergy during the last decade, the possibility that vitamin D status may play a pathogenic role has received recent attention. To determine whether lower levels of neonatal 25-hydroxyvitamin D (25[OH]D) would be observed in children with peanut allergy compared with in population controls. The concentration of 25(OH)D was measured from neonatal dried blood samples by liquid chromatography tandem mass spectrometry. Levels were compared between children with IgE-mediated peanut allergy younger than 72 months assessed during 2008-2011 in a specialist referral clinic in the Australian Capital Territory and population births matched by sex, birth date, and birth location. Odds ratios were calculated for the matched pairs across quintiles of 25(OH)D. Neonatal 25(OH)D levels ranged from 8 to 180 nmol/L (median, 66 nmol/L; interquartile range, 46-93 nmol/L); only 4 children (3%) had levels less than 25 nmol/L, and 24 (20.9%) had levels greater than 100 nmol/L. No significant association was found between socioeconomic or clinical factors and 25(OH)D levels. Compared with the reference group (50-74.9 nmol/L), levels of 75 to 99.9 nmol/L were associated with lower risk of peanut allergy (P = .02). No further reduction was found at levels of 100 nmol/L or higher, and the risk of peanut allergy at levels less than 50 nmol/L was not significantly different from the reference group. The relationship between neonatal 25(OH)D level and childhood peanut allergy was nonlinear, with slightly higher levels (75-99.9 nmol/L) associated with lower risk than those in the reference group (50-74.9 nmol/L). Vitamin D status may be one of many potential factors contributing to childhood peanut allergy pathogenesis. Copyright © 2012 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.