Table 3.

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.