Maternal Vitamin D Status and Risk of Gestational Diabetes: a Meta-Analysis

Background/Aims: Whether maternal vitamin D deficiency is associated with gestational diabetes remains controversial. This meta-analysis aimed to systematically evaluate published evidence on the association between maternal vitamin D status and the risk of gestational diabetes. Methods: We retrieved relevant articles from the PubMed, Medline and Embase databases up to May 2017 for observational studies investigating the association between vitamin D status and the risk of gestational diabetes. Odds ratios (OR) or risk ratios (RR) from individual studies were pooled using the fixed and random effect models. Results: The meta-analysis of 29 observational studies included 28,982 participants, of which 4,634 were diagnosed with gestational diabetes, and showed that maternal vitamin D insufficiency was associated with a significantly increased risk of gestational diabetes by 39% (pooled OR = 1.39, 95%CI = 1.20-1.60) with moderate heterogeneity (I2 = 50.2%; P = 0.001). Moreover, the 25(OH)D level was significantly lower in gestational diabetes cases than in controls with a pooled effect of -4.79 nmol/L (95% CI = -6.43, -3.15). Significant heterogeneity was also detected (I2 = 65.0%, P < 0.001). Further subgroup analysis indicated that this association was also evident in most subpopulations. Conclusion: This meta-analysis indicated a significant association between vitamin D insufficiency and increased risk of gestational diabetes. Further well-designed large-scale clinical trials are essential to verify this association

Association of maternal folate status in the second trimester of pregnancy with the risk of gestational diabetes mellitus

Interest in the high folate status of pregnant women has increased due to its role in the prevention of neural tube defects (NTDs). The effect of increased red blood cell (RBC) folate status during the second trimester of pregnancy on gestational diabetes mellitus (GDM) remains unclear. We measured RBC folate concentrations by competitive protein‐binding assay and obtained clinical information from electronic medical records. Logistic regression analysis was used to explore the associations of RBC folate concentrations with risks of gestational diabetes mellitus (GDM). We further assessed the potential nonlinear relations between continuous log‐transformed RBC folate concentrations and GDM risk by using the restricted cubic splines. We observed high RBC folate concentrations in GDM patients compared to control group [median (interquartile range, IQR), GDM vs. controls: 1,554.03 (1,240.54–1,949.99) vs. 1,478.83 (1,124.60–1,865.71) nmol/L, p = .001]. Notably, high folate concentrations were significantly associated with an increased risk of GDM [RR per 1‐SD increase: 1.16 (1.03, 1.30), p = .012] after adjustment for maternal age, parity, and body mass index (BMI) at enrollment. In the restricted cubic spline model, a test of the null hypothesis of the linear relationship was rejected (p = .001). Our study firstly showed that maternal RBC folate concentrations during the second trimester of pregnancy increase the risk of GDM in a Chinese population. Further randomized clinical trials (RCTs) are warranted to confirm the adverse effect

Association of maternal folate status in the second trimester of pregnancy with the risk of gestational diabetes mellitus

Interest in the high folate status of pregnant women has increased due to its role in the prevention of neural tube defects (NTDs). The effect of increased red blood cell (RBC) folate status during the second trimester of pregnancy on gestational diabetes mellitus (GDM) remains unclear. We measured RBC folate concentrations by competitive protein‐binding assay and obtained clinical information from electronic medical records. Logistic regression analysis was used to explore the associations of RBC folate concentrations with risks of gestational diabetes mellitus (GDM). We further assessed the potential nonlinear relations between continuous log‐transformed RBC folate concentrations and GDM risk by using the restricted cubic splines. We observed high RBC folate concentrations in GDM patients compared to control group [median (interquartile range, IQR), GDM vs. controls: 1,554.03 (1,240.54–1,949.99) vs. 1,478.83 (1,124.60–1,865.71) nmol/L, p = .001]. Notably, high folate concentrations were significantly associated with an increased risk of GDM [RR per 1‐SD increase: 1.16 (1.03, 1.30), p = .012] after adjustment for maternal age, parity, and body mass index (BMI) at enrollment. In the restricted cubic spline model, a test of the null hypothesis of the linear relationship was rejected (p = .001). Our study firstly showed that maternal RBC folate concentrations during the second trimester of pregnancy increase the risk of GDM in a Chinese population. Further randomized clinical trials (RCTs) are warranted to confirm the adverse effect

Association of Maternal Serum 25-Hydroxyvitamin D Concentrations with Risk of Gestational Anemia

Background/Aims: Vitamin D deficiency has been shown to be associated with a greater prevalence of anemia in various healthy and diseased populations by a great deal of observational studies. However, less work has been done to explore this association in pregnant women. The aim of this study was to evaluate the association between maternal serum 25-hydroxyvitamin D [25(OH)D] concentrations and risk of gestational anemia in a large, nested case-control study. Methods: The serum 25(OH)D concentrations was measured by enzyme immunoassay in 775 pregnant women affected with anemia and 1550 controls. Logistic regression analysis was conducted to assess the association of 25(OH)D concentrations with risk of gestational anemia. Results: We found the 25(OH)D concentrations was significantly lower in women affected with anemia than in controls. Logistic regression analyses showed that women with 25(OH)D concentrations < 25.0 nmol/L, from 25.0 to 37.4 nmol/L and from 37.5 to 49.9 nmol/L all had increased risk of anemia when compared with women with concentrations from 50.0 to 74.9 nmol/L. And the risk of anemia was significantly increased with the decreasing concentrations of the serum 25(OH)D in a dose-dependent manner (P for trend = 0.012). For women with concentrations < 50.0 nmol/L, they had an 80% increase in anemia risk (95% CI = 1.45-2.25) after adjustment for confounders. We also observed a nonlinear relationship between the serum 25(OH)D and anemia, with a threshold for 25(OH)D of 50.0 nmol/L existed for anemia. Conclusion: Maternal serum 25(OH)D < 50.0 nmol/L may be a risk factor for gestational anemia, and it should be monitored for the high-risk pregnant women