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The Mediating Effect of Zinc on the Association between Vitamin D and Hemoglobin Status in Kenyan Preschool Children
Author(s) -
Houghton Lisa,
Bailey Karl,
Harper Michelle,
Beaumont Sarah,
Brown Rachel,
Erhardt Jürgen,
Kung'u Martin,
Bautista Maria,
Gibson Rosalind
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.729.10
Subject(s) - anemia , hemoglobin , zinc , medicine , vitamin d and neurology , zinc deficiency (plant disorder) , micronutrient , endocrinology , chemistry , pathology , organic chemistry
In some cases, zinc deficiency has been associated with increased risk for anemia while a growing body of evidence suggests that vitamin D also plays a role in anemia, although the mechanism is unknown. This study investigated the association of serum 25‐hydroxyvitamin D (25OHD) with hemoglobin (Hb) levels and anemia, and tested whether zinc status was a mediating factor in the association between 25OHD and Hb. We used data on 485 children aged 2‐5 y collected in a cross‐sectional survey in southeastern Kenya. Nearly 20% of the children were anemic, 39% were zinc deficient and 25OHD ranged from 47 to 171 nmol/L. After controlling for other factors that may contribute to anemia including age, sex, inflammation and iron deficiency, higher 25OHD levels were associated with decreased risk for anemia (OR 0.977, 95% CI 0.956, 0.997, P=0.02). To examine the extent to which zinc mediates the association between 25OHD and Hb, univariate regression models controlling for all relevant covariates showed there were positive associations between 25OHD and Hb (P=0.03), 25OHD and zinc (P<0.001), and zinc and Hb (P<0.01). With Hb as the dependent variable, including both 25OHD and zinc in a multivariate model rendered 25OHD nonsignificant (P=0.09), whereas the relation between zinc and Hb remained (P=0.01). Sobel‐Goodman test indicated zinc mediated 21% of the total effect of 25OHD on Hb suggesting that vitamin D and the mechanism by which it affects Hb are contingent upon zinc status. Funded by NZ Ministry of Foreign Affairs & Trade.