Table 1.
Characteristics of the 540 blood donors included in the study
| Subjects n (%) | Median (range) | Mean ± SD | |
|---|---|---|---|
| Sex | |||
| Women | 215 (39.8) | ||
| Men | 325 (60.2) | ||
| Age (years) | 41 (16, 71) | 40.5 ± 13.0 | |
| Body weight (kg) | 76 (36, 183) | 77.6 ± 15.2 | |
| Body length (cm) | 177 (155, 205) | 176.6 ± 8.9 | |
| Body mass index (kg/m2) | 24 (12, 61) | 24.8 ± 4.0 | |
| Current smokers | 25 (4.6) | ||
| Subjects who had used a sunbed during the previous month | 23 (4.3) | ||
| Subjects on a sunny holiday during the previous month | 36 (6.7) | ||
| Subjects reporting a vegetarian diet | 26 (4.8) | ||
| Subjects who exercise once a week | 150 (27.7) | ||
| Subjects taking vitamin D supplements | 50 (9.2) | ||
| Female study subjects taking estrogens (contraceptives or HRT) | 24/215 (11.2) | ||
| Subjects on any medication (other than vitamin D) | 62 (11.5) | ||
| Subjects on complementary and alternative medicine | 77 (14.2) | ||
| Serum 25(OH)D (nmol/L) | 60 (10, 224) | 62.8 ± 26.3 | |
| Serum iPTH (ng/L) | 40 (8.7, 151) | 44.0 ± 18.6 | |
| Serum osteocalcin (µg/L) | 14 (5.7, 39) | 15.1 ± 5.4 | |
| Serum calcium (mmol/L) | 2.38 (1.85, 2.82) | 2.39 ± 0.13 | |
| Serum albumin (g/L) | 42 (31, 50) | 41.7 ± 3.1 | |
| Serum phosphate (mmol/L) | 1.3 (0.7, 4.6) | 1.3 ± 0.4 | |
25(OH)D 25-hydroxy vitamin D, iPTH intact parathyroid hormone, HRT hormone replacement therapy