Maternal vitamin D deficiency tied to increased risk of GDM
Women with vitamin D deficiency during early pregnancy may have a higher risk of gestational diabetes mellitus (GDM), according to a study presented at IDF 2017.
“Conflicting results currently exists on the association between vitamin D and glucose metabolism. The role of maternal vitamin D status in GDM is not clear,” said lead author Dr Bishwajit Bhowmik from the Centre for Global Health Research, Diabetic Association of Bangladesh in Dhaka, Bangladesh.
The researchers conducted a randomized controlled trial involving 746 pregnant women (aged 18–28 years) who underwent oral glucose tolerance test (OGTT) and testing for serum 25-hydroxyvitamin D levels at 8–14 weeks of pregnancy. All the participants underwent a second OGTT at 24–28 weeks of pregnancy. GDM cases were identified based on the IADPSG* criteria. [IDF 2017, abstract P0968]
Among all the participants, 176 women were diagnosed with GDM at 24–28 weeks of pregnancy. Compared with women without GDM, women with GDM had significantly lower maternal vitamin D concentrations (45.3 ng/mL vs 38.5 ng/mL; p=0.002) at 8–14 weeks of pregnancy.
Lower vitamin D levels were associated with a higher risk of GDM: GDM incidence occurred at a rate of 31.5 percent in pregnant women deficient for vitamin D (<30 ng/mL), 22 percent in those who were vitamin D insufficient (30–74 ng/mL), and 19 percent in those with sufficient vitamin D levels (≥75 ng/mL).
After adjusting for maternal age and prepregnancy body mass index, women with vitamin D deficiency still had a higher risk of GDM (adjusted odds ratio [adjOR], 1.80, 95 percent confidence interval [CI], 1.01–3.22; p=0.036).
Moreover, being overweight (≥23 kg/m2) further increased the risk of GDM in pregnant women who were vitamin D deficient (adjOR, 3.28, 95 percent CI, 1.89–5.73).
The findings are consistent with a previous study which revealed a significant association between maternal vitamin D deficiency in early pregnancy and an elevated risk for GDM. [PLoS ONE 2008;3:e3753]
Further follow-up studies are warranted to verify the association between GDM and maternal vitamin D status, Bhowmik said.
*IADPSG: International Association for Diabetes in Pregnancy Study Group