WHO/CDC Technical Consultation: Optimal blood folate concentrations in women of reproductive age for prevention of neural tube defects
13-15 August 2012, Emory Conference Center, Atlanta, GA, USA
The World Health Organization convened a consultation on 18-24 October 2005 to examine several issues related to folate and vitamin B12 deficiencies, to review and decide upon the appropriate indicators for assessing the status of these micronutrients. The concentrations suggested for defining serum and red blood folate deficiency in all age groups were based on a point at which homocysteine concentrations became elevated among male and female individuals surveyed in the United States of America, as part of the National Health and Nutrition Examination Survey. However, it was acknowledged that these values represented the minimum of adequacy for metabolic functions and that they were not appropriate for the prevention of NTDs. Therefore, it is necessary to examine the current evidence among women of reproductive age in order to establish the effective and safe concentrations of serum and red blood cell folate that would be associated with the lowest risk of having an NTD-affected pregnancy.
The establishment of optimal blood folate concentrations entails many challenges. There is scarce information on the direct relationship between folic acid intake and blood folate concentrations to NTDs occurrence, from both intervention trials and observational studies. These associations may also be affected by technical, genetic, biological, safety and contextual factors that need to be considered when examining and interpreting the existing data.
In order to strengthen the guidance to Member States and their partners on the use of indicators for assessing folate status at the individual and population level and their application for monitoring and evaluation of birth defect prevention programmes, the Department of Nutrition for Health and Development, World Health Organization, and the Division of Birth Defects and Developmental Disabilities, National Center on Birth Defects and Developmental Disabilities, US Centers for Disease Control and Prevention (CDC), are convening a technical consultation with the following objectives:
- Review the genetic, biological, behavioural and contextual determinants of folate status among women of reproductive age.
- Review the strengths and limitations of current methods used to assess indicators of blood folate status and folate intake.
- Review the strengths and limitations of current methods used to assess NTD prevalence.
- Review all available sources of data on the relationship between folate status (i.e., blood folate and folate intake) and NTD risk from in vitro and in vivo (animal and human) studies.
- Discuss feasible statistical methods for summarizing and modelling the evidence, taking into account their assumptions, strengths and limitations.
- Discuss the proposed methodological approach for retrieving, summarizing and assessing the quality of the evidence related to folate status and NTDs occurrence.
Agreement on the priority questions and methodological approach to estimate optimal blood folate concentrations in women of reproductive age for prevention of NTDs.