Current folate status in Chilean women of childbearing age: findings from the 2016-2017 National Health Survey
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Date
2019
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Abstract
Introduction: Mandatory folic acid (FA) fortification is an effective policy to ensure adequate preconceptional serum folate (SF) levels in women and to reduce the incidence of neural tube defects (NTD). In Chile, FA fortification of wheat flour started in 2000 and significantly reduced NTD prevalence. In 2010, 1:2 Chileans over 65 years old had supraphysiological SF levels. In 2012, FA fortification was reduced from 2.2 to 1.8 mg FA/kg flour. Considering the epidemiological transition in Chile over the last decades and the adjustment of the FA fortification policy in 2012, this study was aimed at describing the current SF levels in women of reproductive age in our country. Methods: 225 women (15-49 years) who participated in the Chilean National Health Survey (NHS) 2016-17 were included in this analysis. NHS 2016-17 used stratified multistage sampling. SF levels were determined by electrochemiluminescence immunoassay, and defined as deficient (≤4.4 ng/ml), normal (4.41 to 20 ng/ml) and supraphysiological [three subcategories: high (20.01 to 25.6 ng/ml), very high (25.61 to 29 ng/ml) and highest (>29 ng/ml)]. Multiple logistic regression analyses were performed using SPSS software (version 17.0). Results: The proportions of women in each decade of life were representative of the national proportions. More than 99% of the women came from urban areas, and near 91% had medium or high educational level. Only 32% of the women declared being current smokers, and 88% declared they were sedentary. Almost 70% of subjects were either overweight or obese, reflecting the current nutritional status of the Chilean population. The SF mean ± SE, median and range were 14.20 ± 0.39, 13.52 and 2.10 - 32.22 ng/ml, respectively. Folate deficiency was present in 0.9% of the women studied, while 7% had supraphysiological levels of the vitamin (3.7% high, 1.6% very high and 1.7% highest levels). Multivariate analyses using linear regression did not show that age, educational level, marital status, parity, smoker/non-smoker or nutritional status had significant effects on FS levels. Conclusion: Folate deficiency in women of reproductive age living in the Metropolitan Region is almost inexistent according to the NHS 2016- 17, showing that most Chilean women are protected from NTD due to folate deficiency. Supraphysiological SF levels were found in 7% of the studied population, lower than the 50% determined in elderly subjects in 2010. Specific policies to reduce the proportion of Chileans at high risk of SF deficiency or excess, in combination with surveillance of FA fortification in flour mills, may help to avoid potential unintended effects of FA fortification in this country. Funding: Chilean Ministry of Health and Pontificia Universidad Católica de Chile.