FOLATE METABOLISM AND PREECLAMPSIA

Association of pre-eclampsia risk with maternal levels of folate, homocysteine and vitamin B12 in Colombia: A case-control study

BACKGROUND

Maternal serum concentrations of folate, homocysteine, and vitamin B12 have been associated with pre-eclampsia. Nevertheless, reported studies involve limited number of cases to reliably assess the nature of these associations. Our aim was to examine the relation of these three biomarkers with pre-eclampsia risk in a large Colombian population.

MATERIALS AND METHODS

Design: A case-control study. Setting: Cases of pre-eclampsia and healthy pregnant controls were recruited at the time of delivery from eight different Colombian cities between 2000 and 2012. Population or Sample: 2978 cases and 4096 controls were studied. Maternal serum concentrations of folate, homocysteine, and vitamin B12 were determined in 1148 (43.6%) cases and 1300 (31.7%) controls. Also, self-reported folic acid supplementation was recorded for 2563 (84%) cases and 3155 (84%) controls. Analysis: Adjusted odds ratios (OR) for pre-eclampsia were estimated for one standard deviation (1SD) increase in log-transformed biomarkers. Furthermore, we conducted analyses to compare women that reported taking folic acid supplementation for different periods during pregnancy. Main Outcomes Measures: Odds ratio for pre-eclampsia.

RESULTS

After adjusting for potential confounders in logistic regression models, the OR for pre-eclampsia was 0.80 (95% CI: 0.72, 0.90) for 1SD increase in log-folate, 1.16 (95%CI: 1.05, 1.27) for 1SD increase in log-homocysteine, and 1.10 (95%CI: 0.99, 1.22) for 1SD increase in log-vitamin B12. No interactions among the biomarkers were identified. Women who self-reported consumption of folic acid (1 mg/day) throughout their pregnancy had an adjusted OR for pre-eclampsia of 0.86 (95%CI: 0.67, 1.09) compared to women that reported no consumption of folic acid at any point during pregnancy.

CONCLUSIONS

Maternal serum concentrations of folate were associated as a protective factor for pre-eclampsia while concentrations of homocysteine were associated as a risk factor. No association between maternal vitamin B12 concentrations and preeclampsia was found.

Potential role of folate in pre-eclampsia

Dietary deficiencies of folate and other B vitamin cofactors involved in one-carbon metabolism, together with genetic polymorphisms in key folate-methionine metabolic pathway enzymes, are associated with increases in circulating plasma homocysteine, reduction in DNA methylation patterns, and genome instability events. All of these biomarkers have also been associated with pre-eclampsia. The aim of this review was to explore the literature and identify potential knowledge gaps in relation to the role of folate at the genomic level in either the etiology or the prevention of pre-eclampsia. A systematic search strategy was designed to identify citations in electronic databases for the following terms: folic acid supplementation AND pre-eclampsia, folic acid supplementation AND genome stability, folate AND genome stability AND pre-eclampsia, folic acid supplementation AND DNA methylation, and folate AND DNA methylation AND pre-eclampsia. Forty-three articles were selected according to predefined selection criteria. The studies included in the present review were not homogeneous, which made pooled analysis of the data very difficult. The present review highlights associations between folate deficiency and certain biomarkers observed in various tissues of women at risk of pre-eclampsia. Further investigation is required to understand the role of folate in either the etiology or the prevention of pre-eclampsia.