The association between serum folate and gestational diabetes mellitus: a large retrospective cohort study in Chinese population

Associations of maternal serum folate, vitamin B12 and their imbalance with gestational diabetes mellitus: The mediation effects of the methionine cycle related metabolites

BACKGROUND & AIMS

Maternal high level of folate and low level of vitamin B12, namely "folate and vitamin B12 imbalance", has been found to be associated with metabolic disorders, such as gestational diabetes mellitus (GDM). The aims of this study were to explore the associations of maternal serum folate, vitamin B12 and their imbalance in early pregnancy with GDM, and to explore the potential mediation effects of the methionine cycle related metabolites on the above associations.

METHODS

This nested case-control study (172 GDM case-control pairs) was conducted based on a prospective birth cohort. Serum concentrations of 5-methyltetrahydrofolate (5-MTHF), vitamin B12 and methionine cycle related metabolites [S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) and Homocysteine (Hcy)] were detected. 5-MTHF (nmol/L)/vitamin B12 (pmol/L) times 1000 was calculated to indicate the imbalance status of folate and vitamin B12. Conditional logistic regression was performed to analyze the associations of 5-MTHF, vitamin B12 and their imbalance with GDM. The mediation effect models were applied to explore the mechanism.

RESULTS

High serum level of 5-MTHF in early pregnancy was related to a higher risk of GDM (OR = 2.00, 95%CI: 1.19-3.37). Compared with the group of the lowest tertile concentration of vitamin B12, the group of the highest concentration had a lower risk of GDM (OR = 0.33, 95%CI: 0.11-0.97). Higher 5-MTHF/vitamin B12 was associated with a higher risk of GDM (OR = 1.67, 95%CI: 1.08-2.56). Besides, no significant mediation effect of methionine cycle related metabolites was found on the associations of folate, vitamin B12 and the imbalance status with the risk of GDM.

CONCLUSIONS

High maternal serum folate, low vitamin B12 levels and the resulting imbalance may increase the risk of GDM. The theory of "folate trap" could not explain the effect of folate, vitamin B12 and their imbalance on GDM.

The association of metabolic profile of folate with diabetic kidney disease: evidence from 2011-2020 cycles of the NHANES

AIMS

Diabetic kidney disease (DKD) develops in approximately 40% of patients with type 2 diabetes mellitus (T2DM). The role of folate metabolites in the progression from T2DM to DKD has not been clearly articulated. Our aim was to assess the association of folate metabolites with DKD.

METHODS

We conducted a cross-sectional study sourced from the U.S. National Health and Nutrition Examination Survey from 2011 to 2020. Several forms of folate were measured. DKD was defined as diabetes with albuminuria or impaired glomerular filtration rate. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression.

RESULTS

Of the 3,461 diabetes patients, 1,349 (38.98%) were diagnosed with DKD. Serum total folate and 5-Methyl-THF were negatively associated with DKD, the OR for comparing extreme quintile were both 0.73 (0.57-0.94). However, a positive association of RBC folate, UMFA, Non-5-Methyl-THF, and MeFox with DKD was observed with extreme quintile OR of 1.41 (1.10-1.82), 1.60 (1.24-2.07), 1.53 (1.20-1.96), and 3.45 (2.65-4.50). Furthermore, the ratio of UMFA to 5-Methyl-THF exhibited a positive association with DKD, with extreme quintile OR of 1.94 (1.50-2.50).

CONCLUSIONS

Our findings suggested that guidelines and interventions highlighting the importance of promoting 5-Methyl-THF and reducing UMFA might have significant benefit for the management of patients with diabetes.

Association of serum folic acid levels in response to fasting blood glucose in early pregnancy with the risk of gestational diabetes mellitus: A retrospective cohort study

OBJECTIVE

With increasingly prevalent folic acid consumption in early pregnancy, concerns about its potentially negative effect on maternal metabolism have been raised. Recent findings regarding folic acid levels in the first trimester and the risk of gestational diabetes mellitus have been inconclusive. The aim of this study was to investigate the association of folic acid status in early pregnancy with gestational diabetes mellitus as well as examine whether glucose levels can be modulated by folic acid status during the same first trimester.

METHODS

This was a retrospective cohort study based on 27 128 Chinese pregnant women who registered during their first prenatal visit from January 2015 to December 2019. Serum folic acid and fasting blood glucose concentrations were measured during the 9th to 13th gestational weeks. Binary logistic regression was applied to estimate the odds ratios of gestational diabetes mellitus by using the serum folic acid levels quartiles with adjustment for major confounders. To investigate the potential effect of modifying key risk factors for gestational diabetes mellitus, we established subgroups, in which analyses were stratified by age (<25, 25-29, 30-34, and ≥35 y), parity (nulliparous and parous), prepregnancy body mass index (< 18.5, 18.5-23.9, and ≥ 24 kg/m2), and family history of diabetes (yes and no).

RESULTS

The positive association between maternal folate concentrations and fasting blood glucose was observed: the risk for hyperglycemia was higher in those in the middle (Q3) and higher (Q4) quartiles compared with those in Q1 and Q2. A higher risk for gestational diabetes mellitus was found in hyperglycemia of early pregnant women with high folate concentrations (Q3: odds ratio = 5.63; 95% CI, 4.56-6.95, and Q4: odds ratio = 5.57; 95% CI, 4.68-6.64) compared with normal fasting glucose mothers with folate concentrations in Q1 and Q2 after accounting for multiple covariables. Similar patterns were observed for different subgroups. Restricted cubic spline plots had a positive correlation of serum folic acid level with fasting blood glucose concentration as well as risk of gestational diabetes mellitus in a nonlinear pattern, with 32.5 nmol/L as the cutoff point for folic acid level.

CONCLUSIONS

Our findings underscore the importance of maintaining an appropriate folic acid concentration for preserving a lower risk of gestational diabetes mellitus, especially in women with relatively higher blood glucose in early pregnancy. Additionally, folic acid concentration > 32.5 nmol/L may be considered a risk factor for gestational diabetes mellitus. This research suggested that folic acid levels should be monitored during the first trimester from the first prenatal checkup to prevent adverse effects of excessive folic acid intake.

The Influence of Maternal Folate Status on Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Maternal folate has been shown to relate to the risk of gestational diabetes mellitus (GDM). However, the existing studies have yielded inconsistent conclusions. The purpose of this study was to systematically review the association between maternal folate status and the risk of GDM. Observational studies up to 31 October 2022 were included. Study characteristics, the means and standard deviations (SDs) of folate levels (serum/red blood cell (RBC)), the odds ratios (ORs) with 95% confidence intervals (CIs) and the time for folate measurement were extracted. Compared with the non-GDM group, serum and RBC folate levels in women with GDM were significantly higher. Our subgroup analysis demonstrated that serum folate levels in the GDM group were significantly higher than in the non-GDM group only in the second trimester. RBC folate levels in the GDM group were significantly higher than in the non-GDM group in the first and second trimesters. Taking serum/RBC folate levels as continuous variables, the adjusted odds ratios of GDM risk showed that increased serum folate concentration rather than RBC folate elevated the risk of GDM. In the descriptive analysis, five studies reported high serum folate levels increased GDM risk, whereas the other five showed no association between serum folate levels and GDM risk. Moreover, the rest three studies pointed out high RBC folate levels increased GDM risk. Altogether we found that the risk of GDM is associated with high serum/plasma and RBC folate levels. Future studies should determine the recommended folic acid cutoff balancing the risk for GDM and fetal malformations.