## Table 3 |
|||||||

Supplementation duration and adherence |
|||||||

Adherence |
Placebo |
Vitamin D |
p |
||||

Mean ± SD |
Median |
Range (min, max) |
Mean ± SD |
Median |
Range (min, max) |
||

Time on study, weeks |
9.7 ± 3.5 | 10.5 | (0, 18) | 9.8 ± 3.3 | 10 | (0, 18) | 0.87^{1} |

Total supplement doses administered |
10.5 ± 3.5 | 11 | (1, 19) | 10.6 ± 3.3 | 11 | (1, 17) | 0.83 |

Total vitamin D administered, mcg |
- | - | - | 9469 ± 2424 | 9625 | (875, 14000) | - |

Adherence, %^{2} |
99.2 ± 2.7 | 100 | (84.6, 100) | 99.4 ± 2.9 | 100 | (80, 100) | 0.79 |

Participants who received 100% of scheduled doses, n (%)^{3} |
68 (91.9%) | 69 (94.5%) | 0.53^{3} |

^{1} p-value for Student’s *t*-test for equality of means.

^{2} Adherence = (number of doses received divided by the number of doses scheduled) x
100. Analysis shown included participants who contributed 25(OH)D measurements beyond
baseline (n = 74 and n = 73 in placebo and vitamin D groups, respectively). Adherence
for participants for whom delivery specimens were available was similar: mean of 99.1%
in the placebo group (n = 63) and 99.3% in the vitamin D group (n = 67). With respect
to longitudinal analyses of changes in 25(OH)D over time, 206/219 serum specimens
(93.5%) in the vitamin D group and 201/213 (94.4%) specimens in the placebo group
were preceded by 100% dose adherence.

^{3} Proportions shown were calculated among participants who contributed 25(OH)D measurements
beyond baseline (74 in placebo group or 73 in the vitamin D group); p value for chi-square
test for proportions. Proportions in the subgroup of participants for whom delivery
specimens were available were similar: 90.5% in the placebo group (n = 63) and 94.0%
in the vitamin D group (n = 67).

Roth * et al.*

Roth * et al.* *Nutrition Journal* 2013 **12**:47 doi:10.1186/1475-2891-12-47