Objectives: To measure the changes in folate consumption and the prevalence of neural tube defects in the British and Irish populations during the past two decades.
Design: Ecological study.
Main outcome measures: Average daily dietary folate consumption for Britain for the period 1980-1996 was estimated from the National Food Survey. Annual neural tube defect prevalences for the same period were obtained from the Oxford Record Linkage Study Neural Tube Defect register, the Glasgow EUROCAT register, and the three Irish EUROCAT registers (Belfast, Dublin and Galway).
Results: Dietary folate consumption increased on average by 1.6% per annum in Scotland and 1.4% in England during the study period. The annual rate of decline of neural tube defect prevalence averaged 10.4% in the Irish population, 8.2% in Glasgow, and 5.2% in Oxfordshire and West Berkshire.
Conclusions: The decline in neural tube defect prevalence observed in all British and Irish populations since the early 1970s continued with the introduction of folate fortification of cereals, which produced measurable increases in average daily folate consumption. Further declines in neural tube defect prevalence may be achieved by targeted folate supplementation during the periconceptual period.