Vitamin D supplement doses taken by multiple sclerosis patients and controls
| Vitamin D3/day | 0 | 400 IU | 800 IU | 1200–1500 IU | Total sample |
| MS patients (n) (%) | 204 (62.0) | 65 (19.8) | 41 (12.5) | 19 (5.7) | 329 (100) |
| Controls (n) (%) | 168 (74.3) | 32 (14.2) | 6 (2.6) | 20 (8.9) | 226 (100) |
Of note, standard multivitamins, usually containing only 400 IU/day, are unlikely to alter serum levels of vitamin D.
IU, international units; MS, multiple sclerosis.