Table 3.
Selected baseline characteristics of study participants by treatment group
| Treatment Group | |||||
|---|---|---|---|---|---|
| Characteristic1 | Placebo (n=23) | Calcium (n=23) | Vitamin D (n=22) | Calcium + Vitamin D (n=23) | P2 |
| Age (yrs) | 58.5 ± 1.7 | 62 ± 1.7 | 60.2 ± 1.7 | 62.1 ± 1.7 | 0.39 |
| Male, n (%) | 16 (69.6) | 16 (69.6) | 16 (72.7) | 16 (69.6) | 0.99 |
| Caucasian, n (%) | 17 (73.9) | 19 (82.6) | 14 (63.6) | 14 (60.9) | |
| African-American, n (%) | 2 (8.7) | 4 (17.4) | 6 (27.3) | 8 (34.8) | 0.12 |
| Body Mass Index (kg/m2) | 30.6 ± 1.3 | 29.4 ± 1.3 | 29.2 ± 1.3 | 31.6 ± 1.3 | 0.51 |
| Total vitamin D intake3 (IU/day) | 279.0 ± 56.5 | 326.0 ± 57.7 | 347.7 ± 57.7 | 401.5 ± 57.7 | 0.50 |
| Total calcium intake3 (mg/day) | 625.3 ±90.6 | 677.6 ± 92.7 | 753.3 ± 92.7 | 733.7 ± 92.7 | 0.74 |
| Sun exposure (hrs/wk) | 4.0 ± 0.6 | 4.2 ± 0.6 | 4.9 ± 0.6 | 3.8 ± 0.6 | 0.61 |
| Travel to warm/sunny location, n (%) | 6 (26.1) | 10 (43.48) | 4 (18.2) | 3 (13.0) | 0.10 |
| Suncreen use, n (%) | |||||
| Never | 16 (30.2) | 9 (17.0) | 12 (22.6) | 16 (30.2) | |
| Rarely | 4 (21.1) | 6 (31.6) | 5 (26.3) | 4 (21.0) | |
| Sometimes to Always | 3 (15.8) | 8 (42.1) | 5 (26.3) | 3 (15.8) | 0.30 |
| Date of blood draw, n (%) | |||||
| Fall (Sep-Nov) | 9 (23.1) | 10 (25.6) | 12 (30.8) | 8 (20.5) | |
| Winter (Dec-Feb) | 9 (34.6) | 6 (23.1) | 3 (11.5) | 8 (30.8) | |
| Summer (May-Aug)4 | 5 (19.2) | 7 (26.9) | 7 (26.9) | 7 (26.9) | 0.60 |
| Plasma 1,25(OH)2D levels (pmol/L) | 94.0 ± 11.4 | 108.9 ± 11.4 | 106.7 ± 11.6 | 90.9 ± 11.4 | 0.60 |
| Plasma 25(OH)D levels (nmol/L) | 51.1 ± 4.3 | 64.2 ± 4.3 | 52.6 ± 4.4 | 52.3 ± 4.3 | 0.12 |
1
Continuous variables presented as means ±SEM; categorical variables as n (%)
2
ANOVA for mean differences for continuous variables; Fisher's exact test for categorical variables
3
Total intake (diet plus supplements), derived from baseline FFQ, energy-adjusted
4
One person had a baseline blood draw in the Spring (May).