. 2010 Mar 5;2(3):299–316. doi: 10.3390/nu2030299

Table 2.

Case control and cohort studies of vitamin B₁₂ and Neural Tube Defects.

Design and reference	Study Details	Main Outcome
Case control [39]	81 NTD cases and 247 controls	In cases only, plasma vitamin B₁₂ and plasma folate affected maternal Red Cell Folate (multiple r = 0.68, p < 0.001).
Case control [40]	84 NTD pregnancies and 110 controls	Women with lower vitamin B₁₂ have increased risk of NTD.
Cohort [41]	Vitamin B₁₂ at 15 weeks' gestation	Vitamin B₁₂ <185 pmol/L associated with the highest risk of NTD.
Case control [42]	46 NTD pregnancies and 44 controls	Lower serum vitamin B₁₂ (p = 0.005) in cases compared to controls
Case control [43]	35 NTD neonates and parents vs 24 normal neonates.	Low vitamin B₁₂ in both the parents of child with NTD.
Case control [44]	89 NTD and 422 controls	Increased NTD risk with lower holo-TC.
Case control ¹[45]	36 NTD vs normal pregnancy.	Low vitamin B₁₂ associated with 2-3 x increased risk for NTD
Case control [46]	46 NTD and 73 control mothers	For NTD holo-TC % (holo-TC/total TCII ) Q1vs Q4 OR = 5.0 (95% CI:1.3, 19.3).
Case control ¹[47]	57 NTD cases and 186 controls	Q1 vs Q5 of vitamin B₁₂ OR = 3.0 (95% CI:1.4, 6.3)
Case control ¹[48]	45 mothers and NTD children vs 83 controls	Case mothers with vitamin B₁₂ ≤ 185 pmol/L OR = 3.5-fold (95% CI:1.3, 8.9) for NTD risk.
Case control [49]	56 NTD babies and mothers vs 97 control children and mothers.	Low vitamin B₁₂levels increase risk of NTD.
Case control ¹[50]	60 NTD cases and 94 controls	NTD for mothers for vitamin B₁₂ levels ≤ 5^th% vs ≥95^th
Case control [51]	32 NTD pregnancies and 132 control pregnancies.	MMA higher in cases vs controls.

¹Study performed in folate fortified population, NTD = Neural tube defects, OR (95%CI) = Odds Ratio and 95% confidence interval, Q4 = 4^th quartile, Q5 = 5^th quintile, RBC = red blood cell, tHcy = total homocysteine concentration, holo-TC = holotranscobalamin II, total TCII = total transcobalamin II, MMA = methylmalonic acid