Table 2.

Distribution of folic acid (≥400 µg/day) supplement intake

Period of ≥400µg/ day folic acid supplement intake	All tumors (NST and mesoderm tumors)	Neuroectoderm-derived tumors (NST)			Mesoderm tumors	Odds ratios (NST versus mesoderm tumors)	Odds ratios (CNST versus mesoderm tumors)	Odds ratios (SNST versus mesoderm tumors)
		All NST	Only CNST	Only SNST
Preconceptional
Yes	37	6	3	3	31	0.44 (0.19–1.02)	0.34 (0.10–1.06)	0.65 (0.25–1.96)
No	185	61	41	20	124
Total	222	67	44	23	155
Before 21 days gestation
Yes	61	8	3	5	53	0.34 (0.17–0.69)	0.19 (0.06–0.60)	0.63 (0.28–1.42)
No	151	59	41	18	102
Total	222	67	44	23	155
Before 36 days gestation
Yes	84	17	11	6	67	0.58 (0.37–0.91)	0.57 (0.33–0.99)	0.60 (0.29–1.22)
No	138	50	33	17	88
Total	222	67	44	23	155
During any period
Yes	179	56	33	23	123	1.05 (0.92–1.20)	0.94 (0.78–1.14)
No	43	11	11	0	32
Total	222	67	44	23	155

Distribution of folic acid intake by period is shown above. OR of folic acid supplement intake were significantly lower in children with NST than controls, but when NST were broken down by CNST and SNST, OR only remained significant for CNST in which folic acid intake occurred before the 21st (0.19, 0.06–0.60) or 36th day (0.57, 0.33–0.99) postconception