Table 3: Vitamin B12 levels, Methylmalonic acid levels, and vitamin B12 deficiency.
RA (n = 45) | AITD (n = 36) | Control (n = 44) | 'p' value | |
Vitamin B12 levels (pg/mL) | 726.3 ± 392.9 | 606.8 ± 281.8 | 655.8 ± 342.7 | 0.297 |
Methylmalonic acid levels (nmol/L) | 202.4 ± 79.3 | 216.1 ± 125.1 | 190.5 ± 118.4 | 0.575 |
Vitamin B12 < 200 pg/mL (Prevalence %) | 0 (0%) | 0 (0%) | 1 (2.3%) | NS |
Vitamin B12 < 350 pg/mL (Prevalence %) | 3 (6.7%) | 6 (16.7%) | 4 (9.1%) | NS |
Vitamin B12 < 220 pmol/L AND Methylmalonic acid > 378 nmol/L* (Prevalence %) |
0 (0%) | 1 (2.8%) | 1 (2.3%) | NS |
Key: *Marks PW, et al. NEJM. 2004; 351: 1338.
The one subject in the control arm with a serum vitamin B12 level less than 200 pg/mL was the same subject who also had a serum vitamin B12 < 220 pmol/L and Methylmalonic acid > 378 nmol/L
To convert values for serum vitamin B12 from picograms per milliliter to picomoles per liter, multiply by 0.7378.