Cord blood 25(OH)D levels and the subsequent risk of lower respiratory tract infections in early childhood: the Ulm birth cohort
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Lower respiratory tract infections (LRTIs) are a major cause of hospitalization in infants. Research suggests that immunomodulatory properties of vitamin D may influence LRTI risk. This study’s objective was to examine whether 25-hydroxyvitamin D [25(OH)D] concentrations in cord blood influenced susceptibility to LRTI in the first year of life. Data was analyzed from a prospective birth cohort of 777 mother-infant pairs based in Ulm, Germany. Relative risks (RRs) of LRTI in relation to 25(OH)D cord blood levels were estimated by log-binomial regression after adjustment for potential confounders. To account for seasonal variation in both vitamin D levels and infections, we examined the association in different seasons. Analyses were conducted using clinical predefined cutpoints, quartiles, and season-standardized 25(OH)D quartiles. We observed a statistically significant association between 25(OH)D status in cord blood and risk of LRTI across the year using clinical cutpoints. The adjusted RR of LRTI for individuals with vitamin D deficiency (<25 nmol/L) in comparison to the referent category (>50 nmol/L) was 1.32 [95 % confidence interval (CI) 1.00, 1.73]. The association differed by maternal allergy status; children born to mothers without allergy demonstrated a RR of 1.45 (95 % CI 1.03, 2.03). The effect was largely driven by a strong association between 25(OH)D and LRTI in infants born in fall with a RR of 3.07 (95 % CI 1.37, 6.87). Our findings suggest that vitamin D deficiency at birth is associated with increased risk of LRTI particularly in infants born to mothers without allergy. The association seems strongest in infants born in fall.
KeywordsVitamin D Birth cohort Lower respiratory tract infection Prospective study
We highly appreciate the contribution of Dr. Jon Genuneit on discussion of the analysis and an earlier draft of the paper. We also thank Professor Andrea Heinzmann for her great input into the discussion. The study was supported by grants of the German Research Council (BR 1704/3-1, BR 1704/3). This study was supported by the German Federal Ministry of Education and Research (BMBF 01EO1303). The authors are responsible for the contents of this publication.
Conflict of interest
No potential conflicts of interest relevant to this article were reported. All researchers and authors were independent of the funding source. No funding source or sponsor was involved in the design or performance of the study; in the collection, management, analyses, or interpretation of the data; or in the preparation, review, approval, or decision to submit the manuscript for publication.
- 11.Clancy N, Onwuneme C, Carroll A, et al. Vitamin D and neonatal immune function. J Matern Fetal Neonatal Med. 2012;10:10.Google Scholar
- 13.Cavalier E, Wallace AM, Carlisi A, Chapelle JP, Delanaye P, Souberbielle JC. Cross-reactivity of 25-hydroxy vitamin D2 from different commercial immunoassays for 25-hydroxy vitamin D: an evaluation without spiked samples. Clin Chem Lab Med. 2011;49(3):555–8. doi: 10.1515/cclm.2011.072.PubMedCrossRefGoogle Scholar
- 20.Wuertz C, Gilbert P, Baier W, Kunz C. Cross-sectional study of factors that influence the 25-hydroxyvitamin D status in pregnant women and in cord blood in Germany. Br J Nutr. 2013;1–8. doi: 10.1017/s0007114513001438.
- 31.Prescott SL, Noakes P, Chow BW, et al. Presymptomatic differences in Toll-like receptor function in infants who have allergy. J Allergy Clin Immunol. 2008;122(2):391–9, 9 e1-5. doi: 10.1016/j.jaci.2008.04.042.
- 34.Schottker B, Jansen EH, Haug U, Schomburg L, Kohrle J, Brenner H. Standardization of misleading immunoassay based 25-hydroxyvitamin D levels with liquid chromatography tandem-mass spectrometry in a large cohort study. PLoS ONE. 2012;7(11):e48774. doi: 10.1371/journal.pone.0048774.PubMedCentralPubMedCrossRefGoogle Scholar