Fig. 2.

The VDBP 1S allele was associated with the highest circulating 25-D concentrations in children reaching the vitD RDA. a Comparisons of mean 25-D between children of different VDBP genotypes who regularly reached vitD RDA (normalized as >25 IU/kg) or not at the time of annual serum collection (308 total samples). No group of n ≤ 5 compared (affected only 2/2 genotype). b Mean 25-D in children reaching the vitD RDA compared between subjects who carried the 1S allele and those who did not (47 and 33, respectively). If an individual child had more than one such sample, 25-D values were averaged. c Association of VDBP genotypes to mean 25-D within the same children who were both below and above vitD RDA at different annual serum collections (55 total subjects). Also shown are children grouped by carriers of the 1S allele per se. Dashed line in each graph represents threshold serum concentration of ≥75 nmol/L 25-D. vitD, Vitamin D, VDBP, vitamin D binding protein; 25-D, 25-hydroxyvitamin D, RDA recommended daily allowance