Review of current evidence for folate in the prevention of neural tube defects

Abstract

The incidence of neural tube defects (NTD) among black South Africans living in urban areas is low compared with reports of NTD incidence in rural areas  A NTD incidence of 0.95 per 1000 live births was reported in Cape Town,l while an incidence of 0.99 per 1 000 live births was reported in a study performed at Kalafong Academic Hospital, Pretoria.' In contrast, the prevalence of NTD in the black population in rural Transkei was 6.13 per 1 000 live births,' and in rural Northern Province it was 3.55 per 1 000 live births.' In view of the association between folic acid status and NiD, we  performed a study in rural and urban communities to determine whether folate or vitamin B₁₂ status and/or abnormal homocyst(e)ine metabolism could explain why the incidence of NTD in rural areas is so high. (Homocyst(e)me (tHcy) refers to the sum of concentrations of free homocysteine, protein-bound homocysteine, the disulphide homocystine, and the mixed disulphide homocysteine-cysteine.)