Cord blood vitamin D tied to cord blood insulin, C-peptide
Vitamin D appears to contribute to the regulation of foetal insulin secretion, which may affect glucose regulation and growth, suggests a recent study.
The investigators examined mother-newborn pairs from two cohorts: Project Viva (n=862 pairs) and Genetics of Glucose Regulation in Gestation and Growth (Gen3G; n=660 pairs). They also analysed the associations of cord blood hormones with maternal 25-hydroxyvitamin D (25[OH]D) using generalized additive models with nonlinear spline terms, and with cord blood 25(OH)D using multivariable linear regression models.
“We hypothesized that maternal 25(OH)D during pregnancy and cord blood 25(OH)D would both be positively associated with cord blood insulin and C-peptide,” the investigators said.
The levels of 25(OH)D were <75 nmol/L in >70 percent of mothers and in 85 percent of newborns.
An association existed between maternal and cord blood 25(OH)D levels (Project Viva: r, 0.58; Gen3G: r, 0.37). The association of maternal 25(OH)D with cord blood insulin and C-peptide showed an inverted U-shape in both cohorts, while the relationship between cord blood 25(OH)D and cord blood hormones was linear.
Fully adjusted models revealed that each 10-nmol/L increase in cord blood (25(OH)D correlated with higher cord blood insulin and C-peptide concentrations: 3.7 percent (95 percent CI, 0.09‑7.5) and 3.2 percent (0.8‑5.6), respectively, in Project Viva; 2.2 percent (‑0.1 to 4.6) and 3.6 percent (1.0‑6.3), respectively, in Gen3G.
“Vitamin D may be important for prenatal programming of insulin and glucose regulation, but maternal vitamin D deficiency during pregnancy is common,” the investigators said.