Maternal serum vitamin B12, folate and homocysteine and the risk of neural tube defects in the offspring in a high-risk area of China

Objective: To examine the association between the risk of neural tube defects (NTD) and maternal serum vitamin B-12, folate and homocysteine in a high-risk area of China. Design: A case-control study was carried out in Luliang mountain area of Shanxi Province. Subjects/setting: A total of eighty-four NTD pregnancies and 110 matched controls were included in the study; their serum vitamin B-12 and folate concentrations were measured by chemiluminescent immunoenzyme assy and total homocysteine concentrations by fluorescent polarisation immunoassy. Results: Serum vitamin B-12 and folate concentrations were lower in NTD-affected pregnant women than in controls (P<0.01). Serum total homocysteine was higher in the NTD group than in controls at less than 21 weeks of gestation (P<0.01). Adjusted odds ratios revealed that women with lower vitamin B(12 ()adjusted OR=4.96; 95% CI 1.94, 12.67) and folate (adjusted OR=3.23; 95% CI 1.33, 7.85) concentrations had a higher risk of NTD compared to controls. Based in dietary analysis, less consumption of meat, egg or milk, fresh vegetables and fruit intake would increase the risk of NTD. Conclusions: Lower serum concentrations of folate and vitamin B-12 are related to the increased risk of NTD in high-risk populations. Both folate and vitamin B-12 intake insufficient could contribute to the increased risk of NTD. A dietary supplement, combining folate and vitamin B-12, might be an effective measure to decrease the NTD incidence in these areas.