Figure 1.

Changes in 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D [1,25(OH)₂D], and fibroblast growth factor 23 (FGF23) with ergocalciferol administration. Mean (±SEM) of (A) 25OHD measured by liquid chromatography/tandem mass spectroscopy (the horizontal line represents the lower limit of normal), (B) 1,25(OH)₂D (the horizontal lines represent the normal range), and (C) FGF23 (the horizontal lines represent the normal range based on our prior data) at weeks 0, 4, 8, and 12 in the vitamin D (solid line) and placebo (dashed line) groups. P value assesses change over time by repeated-measures ANOVA compared with placebo. Systeme International conversion factors are 25OHD (nM), 2.496; and 1,25(OH)₂D (pmol/L), 2.6.