Fig. 4.

The VDBP 1S allele is associated with mean serum 25-D >75 nmol/L in African-American children who meet or exceed RDA. a Comparisons of mean 25-D in three groups of African-American children (93 serum samples; 1S group: genotypes 1S/1F, 1S/2, and 1S/1S; no 1S group: 1F/1F and 1F/2) who reached vitD RDA or not at the time of annual serum collection. b Comparisons of 25-D in serum samples collected at the time of lowest or highest daily vitD intake from African-American children either carrying the 1S allele or not (12 and 43 subjects, respectively); also, averaged 25-D values of all serum samples per subject either below or above RDA. Dashed line in each graph represents threshold serum concentration of ≥75 nmol/L 25-D