Expectant mothers look over! Fudan University study: supplementing this vitamin can reduce the risk of gestational diabetes by 37%!

Vitamin D deficiency during pregnancy is a common public health problem
.
There is growing concern about several non-skeletal effects of vitamin D deficiency during pregnancy, including its effects
on placental function, glucose homeostasis, infection, and inflammatory responses.
There is evidence that vitamin D deficiency during pregnancy is associated
with perinatal complications such as GDM, pre-eclampsia, spontaneous abortion, preterm birth, and neurodevelopment.
The evidence for the relationship between vitamin D status and GDM has been investigated
in depth.
The different results in the literature can be attributed in part to differences in vitamin D deficiency cut-off values, timing of serum collection, dose of calcium supplementation, acceptability of calcium supplementation, population dietary habits, socioeconomic status, and nutrition-related genes
.

Therefore, understanding the role of vitamin D in the development of GDM is critical
to developing possible personalized supplementation recommendations to prevent GDM.
The purpose of the study was to assess vitamin D status in early pregnancy and to understand its association
with GDM risk based on data from the urban population of Shanghai, China.

The retrospective cohort included a total of 7816 pregnant women who underwent a 75 g oral glucose tolerance test (OGTT)
at 24 to 28 weeks' gestation.
Demographic information of participants, including maternal age, preconceptional body mass index (BMI), gestational age, parity, blood collection season, serum 25-hydroxyvitamin D [25(OH)D] data, and other blood biomarker data
at 6 to 14 weeks' gestation was retrospectively extracted from hospital information system records.

In this cohort, the prevalence of GDM was 8.
6%, and the prevalence of vitamin D deficiency and insufficiency in early pregnancy was 53.
1% and 38.
5%,
respectively.
The mean serum 25(OH)D concentration was 19.
6±7.
5 ng/mL
.

A total of 669 (8.
6%) pregnant women were diagnosed with GDM
at 24-28 weeks' gestation.
Compared with the non-GDM group, the GDM group was older, had a higher preconception BMI, higher levels of TGs, HbA1c, and fasting blood glucose, and a higher
proportion of women who were in labor, overweight, and obese.
Retrospectively comparing serum 25(OH)D levels in early pregnancy, mean concentrations were lower in the GDM group and lower in the vitamin D adequacy group than in the non-GDM group
.

Relationship analysis
was performed using 25(OH)D concentrations as continuous and categorical variables.
Table 3 shows the results
of GDM logistic regression analysis of different models associated with serum 25(OH)D concentration categories.
Logistic model analysis showed no significant difference in the risk of GDM in women with 25(OH)D concentrations ranging from 20 to 29.
9 ng/ml compared with women with 25(OH)D concentrations < 20 ng/ml (OR: 1.
04; 95%CI：0.
88-1.
23; P = 0.
652), and women with 25(OH)D concentrations ≥ 30 ng/ml had a significantly lower
risk of GDM.
The RCS model showed that vitamin D status was associated with GDM in an inverted J-shaped association after adjusting for maternal age and pre-pregnancy BMI (nonlinear trend P=0.
012).

There was no significant correlation between vitamin D levels and GDM at 25(OH)D concentrations of <20 ng/mL, GDM risk decreased at 25(OH)D concentrations of >20 ng/mL, and continued to decrease
when 25(OH)D concentrations were >30 ng/mL.

Overall, this retrospective cohort study of 7,816 Chinese women showed that vitamin D deficiencies and insufficiency are common
in early pregnancy.
A nonlinear association
of vitamin D status with GDM was observed.
Vitamin D levels ≥ 20 ng/mL are important protective factors
against GDM.

Original source:

Cheng Y, Chen J, Li T, Pei J, Fan Y, He M, Liu S, Liu J, Zhang Q, Cheng H.
Maternal vitamin D status in early pregnancy and its association with gestational diabetes mellitus in Shanghai: a retrospective cohort study.
BMC Pregnancy Childbirth.
2022 Nov 5; 22(1):819.
doi: 10.
1186/s12884-022-05149-1.
PMID: 36335302; PMCID: PMC9636619.