Subgroup metanalysis of indicator of micronutrients
| Subgroup | Included studies (n) | Participants (n) | OR (95% CI) | P value | Heterogenicity (χ2) | |
| Case | Control | |||||
| Vitamin B12 | 2 | 115 | 188 | 0.74 (0.45 to 1.21) | 0.22 | 0.1 |
| Folate | 2 | 249 | 197 | 1.07 (0.73 to 1.58) | 0.73 | 3.85 |
| Ferritin | 2 | 121 | 187 | 0.81 (0.51 to 1.31) | 0.40 | 0.77 |
| IDA | 2 | 68 | 149 | 16.23 (4.19 to 62.93) | <0.001 | 0.41 |