40 percent less likely to get adequate vitamin D response if have certain genes – Jan 2013

Vitamin D intake and season modify the effects of the GC and CYP2R1 genes on 25-hydroxyvitamin D concentrations.

J Nutr. 2013 Jan;143(1):17-26. doi: 10.3945/jn.112.169482. Epub 2012 Nov 28.
Engelman CD, Meyers KJ, Iyengar SK, Liu Z, Karki CK, Igo RP Jr, Truitt B, Robinson J, Sarto GE, Wallace R, Blodi BA, Klein ML, Tinker L, LeBlanc ES, Jackson RD, Song Y, Manson JE, Mares JA, Millen AE.
Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA. cengelman@wisc.edu.

Press Release for this study

Abstract

Vitamin D deficiency (defined by the blood concentration of 25-hydroxyvitamin D [25(OH)D]} has been associated with many adverse health outcomes. Genetic and nongenetic factors account for variation in 25(OH)D, but the role of interactions between these factors is unknown. To assess this, we examined 1204 women of European descent from the Carotenoids in Age-Related Eye Disease Study, an ancillary study of the Women's Health Initiative Observational Study. Twenty-nine single nucleotide polymorphisms (SNPs) in 4 genes, GC, CYP2R1, DHCR7, and CYP24A1, from recent meta-analyses of 25(OH)D genome-wide association studies were genotyped. Associations between these SNPs and 25(OH)D were tested using generalized linear regression under an additive genetic model adjusted for age, blood draw month, and ancestry. Results were stratified by season of blood draw and, separately, vitamin D intake for the 6 SNPs showing a significant association with 25(OH)D at the P < 0.01 level. Two nonsynonymous SNPs in GC and 4 SNPs in CYP2R1 were strongly associated with 25(OH)D in individuals whose blood was drawn in summer (P ≤ 0.002) but not winter months and, independently, in individuals with vitamin D intakes ≥400 (P ≤ 0.004) but not <400 IU/d (10 μg/d). This effect modification, if confirmed, has important implications for the design of genetic studies for all health outcomes and for public health recommendations and clinical practice guidelines regarding the achievement of adequate vitamin D status.

PMID: 23190755

See also VitaminDWiki

• Vitamin D levels are strongly associated with genes: overview of twin studies – Nov 2012
• Trying to understand the effect of genetics vitamin D levels in the blood – Jan 2013
• All items in Genetics and vitamin D 332 items
• CYP24A1 enzyme and Vitamin D
• Mice lacking CYP2R1 enzyme activate about half of much vitamin D – Sept 2013

See also web

• Clinical trials of Genes and Vitamin D 58 as of July 2013