Table 7. Studies Included in Systematic Reviews of the Effectiveness of Vitamin B12 on Cognitive Function.
| Author, Yeara | Vitamin B12 Deficient? | Cognitive Impairment or Dementia? | Duration of Followup (months) |
|---|---|---|---|
| De Jager et al, 2012 (48) | No | Yes (mild cognitive impairment) | 24 |
| Kwok et al, 2011 (49) | No | Yes (mild to moderate AD or vascular dementia) | 24 |
| Ford et al, 2010 (50) | Not reported | Unclear | 24 |
| Aisen et al, 2008 (51) | No | Yes (mild to moderate AD) | 18 |
| Kang et al, 2008 (52) | Not reported | Not reported at baseline | 60 |
| Eussen et al, 2006 (53) | Yes (100–200 pmol/L) | Mixed (40% mild to moderate cognitive impairment); results not stratified for patients with cognitive impairment | 6 |
| McMahon et al, 2006 (54) | Likely (high Hcy implies low B12) | No | 24 |
| Lewerin et al, 2005 (55) | No | Unclear | 4 |
| Stott et al, 2005 (56) | No | Mixed (mild or moderate cognitive impairment included) | 12 |
| Garcia et al, 2004 (57) | No | No | 6 |
| Hvas et al, 2004 (58) | Likely (increased MMA implies low B12) | Mixed (1/3 cognitive impairment) | 3 |
| Clarke et al, 2003 (59) | No | Yes (mild to moderate dementia) | 3 |
| Bryan et al, 2002 (60) | Not reported | No | 1 |
| Seal et al, 2002 (61) | Yes (100–150 pmol/L) | Mixed (1/3 cognitive impairment); results not stratified for patients with cognitive impairment | 1 |
| Kwok et al, 1998 (62) | Yes (< 120 pmol/L) | Mixed (20% with dementia); results not stratified for patients with dementia | 4 |
| De la Fourniere et al, 1997 (63) | Yes (< 178 pmol/L) | Yes (all AD) | Not reported |
| Kral et al, 1970 (64) | N/A | N/A | N/A |
a
Studies where B12 was part of the treatment arm.
Abbreviations: AD, Alzheimer disease; Hcy, homocysteine; MMA, methylmaloninc acid; N/A, not applicable.