RBC folate concentrations >748 nmol/L by treatment group at baseline, 16 and 20 weeks
| Treatment | N | Baseline* | 16 weeks* | Relative risk (95% CI)† | P value‡ | 20 weeks* | Relative risk (95% CI)† | P value‡ |
| 2.8 mg folic acid§ | 111 | 9 (8%) | 74 (68%) | 16.0 (6.1 to 42.3) | <0.0001 | 55 (53%) | 14.6 (5.2 to 41.1) | <0.0001 |
| 0.4 mg folic acid | 110 | 4 (4%) | 9 (8%) | 2.2 (0.7 to 6.8) | 0.17 | 12 (11%) | 3.5 (1.1 to 10.7) | 0.03 |
| 0 mg folic acid | 110 | 3 (3%) | 4 (3%) | Reference | 3 (3%) | Reference |
*Values are n (%) of women with RBC folate concentrations greater than 748 nmol/L based on the raw data of the intention-to-treat population.
†Relative risks are relative to the 0 mg folic acid group and are adjusted for baseline RBC folate levels.
‡Statistical significance set at p<0.0167 for pairwise comparisons of treatment groups.
§RBC folate relative risk for 2.8 mg vs 0.4 mg was 7.3 (95% CI 3.9 to 13.7; p<0.0001) at 16 weeks and 4.2 (95% CI 2.4 to 7.3; p<0.0001) at 20 weeks. P=0.31 for treatment group by time point interaction test.
RBC, red blood cell.