Poster Topical Area: Maternal, Perinatal and Pediatric Nutrition
Location: Hall D
Poster Board Number: 385
Objectives: Gestational vitamin D status may contribute to prenatal programming of the insulin axis and glucose regulation, and low maternal vitamin D has been linked to impaired fetal growth, adverse postnatal growth patterns, and insulin resistance in the offspring. Fetal growth is also positively associated with cord blood insulin and c-peptide concentrations. We hypothesized that maternal circulating 25-hydroxyvitamin D (25(OH)D) during pregnancy and cord blood 25(OH)D would both be positively associated with cord blood insulin and c-peptide.
Methods: We studied mother-infant pairs enrolled in Project Viva (n=862; Boston, MA) and Genetics of Glucose Regulation in Gestation and Growth (Gen3G; n=660; Sherbrooke, Canada). Both cohorts collected blood samples and other data from mothers during pregnancy and umbilical cord blood samples at birth. We examined associations of maternal and cord blood 25(OH)D with log-transformed cord blood insulin and c-peptide concentrations using multivariable linear regression models and generalized additive models with nonlinear splines.
Results: Mean (SD) maternal 25(OH)D levels were 59 (20) and 64 (20) nmol/L and cord blood levels were 46 (19) and 53 (18) in Project Viva and Gen3G, respectively. Correlations between maternal and cord blood 25(OH)D levels were 0.58 in Project Viva and 0.37 in Gen3G. In both cohorts, higher maternal pre-pregnancy BMI was associated with lower maternal and cord blood 25(OH)D and higher cord blood insulin and c-peptide. After adjusting for season, child sex, maternal race/ethnicity, age at enrollment, parity, smoking and pre-pregnancy BMI, each 10-nmol/L increase in cord blood 25(OH)D was associated with 3.6% (95% CI: 0.0, 7.3) higher cord blood insulin concentration and a 3.2% (95% CI: 0.8, 5.6) higher c-peptide concentration in Project Viva, and with 2.2% (95% CI: -0.2, 4.5) higher cord blood insulin concentration and 3.6% (95% CI: 1.0, 6.3) higher c-peptide concentration in Gen3G. Maternal 25(OH)D appeared to have non-linear, inverse U-shaped associations with the cord blood hormones, with higher insulin and c-peptide among mothers with 25(OH)D in the range of ~50-90 nmol/L.
Conclusions: Vitamin D may play a role in regulating fetal insulin secretion, with a potential long-term impact on postnatal glucose regulation and growth.
Harvard Pilgrim Health Care Institute/Harvard Medical School