OBJECTIVE To determine an optimal population red blood cell (RBC) folate concentration for the prevention of neural tube birth defects. DESIGN Bayesian model. SETTING Data from two population based studies in China. PARTICIPANTS 247,831 participants in a prospective community intervention project in China (1993-95) to prevent neural tube defects with 400 μg/day folic acid supplementation ...

We evaluated folate status of child-bearing age women diagnosed with abnormal pap smear in the US post-folic acid (FA) fortification era and assessed the determinants of NTD-protective and supra-physiologic (SP) concentrations of folate. The distribution of 843 women according to NTD-protective concentrations of RBC folate, plasma folate and SP concentrations of plasma folate were tested in rel...

Recent studies have implicated folic acid as an important determinant of normal human growth, development, and function. Insufficient folate levels appear to be a risk factor for neural tube defects (NTD), as well as for several chronic diseases of adulthood. However, relatively little is known about the factors that influence folate status in the general population. To estimate the relative co...

The NHANES has monitored folate status of the U.S. population from prefortification (1988-1994) to postfortification (1999-2010) by measuring serum and RBC folate concentrations. The Bio-Rad radioassay (BR) was used from 1988 to 2006, and the microbiologic assay (MBA) was used from 2007 to 2010. The MBA produces higher concentrations than the BR and is considered to be more accurate. Thus, to b...

BACKGROUND In 1998, mandatory folic acid fortification of white flour and select cereal grain products was implemented in Canada with the intention to increase dietary folate intakes of reproducing women. Folic acid fortification has produced a dramatic increase in blood folate concentrations among reproductive age women, and a reduction in neural tube defect (NTD)-affected pregnancies. In resp...

OBJECTIVES To assess the folate and vitamin B12 status of a group of Vietnamese women of reproductive age and to estimate the rate of neural tube defects (NTD) based on red blood cell (RBC) folate concentrations. DESIGN AND SUBJECTS A representative sample of non-pregnant women (15-49 years) living in Hanoi City (n 244) and Hai Duong Province (n 245). MEASURES RBC folate, plasma vitamin B12...

One-fifth of Canadian women of childbearing age (WCBA) have red blood cell (RBC) folate concentrations below those considered optimal for neural tube defect risk reduction (≥906 nmol·L(-1)). Determinants of optimal concentrations have not been examined in a nationally representative sample of Canadian WCBA since food fortification with folic acid was implemented. This study explored correlates ...

OBJECTIVES To assess the percentage of women of childbearing age with suboptimal levels of folate for protecting against neural tube defects (<906 nM), and assess folate status among the elderly. METHODS A total of 1,035 anonymous blood samples from a centralized clinical laboratory, with a catchment area across the Greater Toronto Area, were assessed for red blood cell (RBC) folate concen...

Folate is found naturally in foods or as synthetic folic acid in dietary supplements and fortified foods. Adequate periconceptional folic acid intake can prevent neural tube defects. Folate intake impacts blood folate concentration; however, the dose-response between natural food folate and blood folate concentrations has not been well described. We estimated this association among healthy fema...

OBJECTIVE Homozygosity for variants of the methylenetetrahydrofolate reductase (MTHFR) gene is associated with decreased risk for colorectal cancer. We have investigated the relationships between two variants of the MTHFR gene (C677T and A1298C) and blood folate, homocysteine, and genomic stability (strand breakage, misincorporated uracil, and global cytosine methylation in lymphocytes) in a st...