Figure 1.

Serum 25-OHD (A) and calcium (B) at 0, 2, 4, 6, and 8 wk (August to October) and 8 wk off therapy (December) in the short-term study, by treatment group. The box plot shows the median (50th percentile) as a line and the first (25th percentile) and third quartile (75th percentile) of the distribution as the lower and upper parts of the box. The whiskers shown above and below the boxes represent the largest and smallest observed values that are less than 1.5 box lengths from the end of the box. Analyses conducted using repeated-measures ANOVA. In the Sigma group, mean 25-OHD was 49 ± 12 ng/ml at baseline, 53 ± 19 ng/ml (P = 0.440) after 8 wk of supplementation and decreased to 38 ± 10 ng/ml at 2 wk off therapy (P = 0.01 vs. the 8 wk value). In the Vigantol group, mean 25-OHD concentration group increased from 37 ± 6 ng/ml at baseline to 54 ± 20 ng/ml (P = 0.043) after 8 wk of supplementation and then decreased to 33 ± 7 ng/ml at 2 wk off therapy (P = 0.018 compared with the 8 wk value). *, No significant difference in 25-OHD levels between D₃ groups at similar time points; †, 25-OHD levels were significantly higher in D₃ group(s), compared with the placebo group, at 8 wk and 8 wk off therapy (P < 0.05). There were no significant differences in serum calcium levels achieved at 8 wk and 8 wk off therapy among the three groups (ANOVA). Biochemical assays are reported in metric units. To convert from metric to SI units, multiply calcium by 0.25 (millimoles per liter); 25-OHD by 2.496 (nanomoles per liter).