Table 1.
Descriptive statistics on study measures.
| Study measure | Continuous Scale | Categorical Scale |
|---|---|---|
| Depressive symptoms | Mean (SD) | Clinically significant |
| W1 | 14.04 (9.11) | 34% |
| W2 | 15.23 (9.68) | 42% |
| W3 | 14.13 (10.15) | 39% |
| W4 | 13.21 (9.55) | 35% |
| W5 | 13.43 (10.22) | 36% |
| Vitamin D3 (ng/mL), blood concentration | Mean (SD) | Sufficiency1 |
| W1 | 33.40 (12.42) | 31% insufficient |
| 10% deficient | ||
| W5 | 32.36 (12.17) | 31% insufficient |
| 15% deficient | ||
| Body mass index (kg/m2) | Mean (SD) | CDC cut-points |
| W1 | 24.79 (4.79) | 1% underweight |
| 62% normal | ||
| 27% overweight | ||
| 10% obese | ||
| Dietary vitamin D intake (µg/month) | Mean (SD) | |
| W1 unadjusted2 | 182.45 (178.37) | |
| W1 ln-transformed | 4.79 (0.97) | |
| Exercise (minutes/week) | Mean (SD) | |
| W1 | 282.31 (193.68) | |
| Time outside (minutes/week) | Mean (SD) | |
| W1 unadjusted | 522.97 (520.29) | |
| W1 square root-transformed | 20.32 (10.52) | |
| Ascorbate (µM), blood concentration | Mean (SD) | |
| W1 | 59.31 (21.79) |
Note.
1
rates based on total vitamin D (D2 + D3).
2
for reference, current U.S. recommended dietary allowance is 15 µg per day (~450 µg/month; Holick et al., 2011)