Associations of Free, Bioavailable, and Total 25-Hydroxyvitamin D with Neonatal Birth Anthropometry and Calcium Homeostasis in Mother-Child Pairs in a Sunny Mediterranean Region.

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British Journal Of Nutrition

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Sufficient vitamin D status is crucial for successful pregnancy and fetal development. The assessment of 25-hydroxyvitamin D [25(OH)D] concentrations is commonly used to evaluate vitamin D status. Additionally, bioavailable 25(OH)D, encompassing both free and albumin-bound fractions, is considered significant for pregnancy-related outcomes. However, limited research has been conducted on the correlation between free and bioavailable 25(OH)D concentrations and neonatal parameters.Our objective was to examine the interrelated biodynamics of maternal and neonatal total, free, and bioavailable 25(OH)D in maternal-neonatal dyads at birth, and their associations with homeostasis and neonatal birth anthropometry.We analyzed a cohort of 70 full-term mother-child pairs. At birth, we evaluated maternal and neonatal concentrations of total, free, and bioavailable 25(OH)D, as well as calcium and parathyroid hormone concentrations. Additionally, we assessed neonatal anthropometric profiles, including birth weight, head circumference, chest circumference, and abdomen circumference.We found positive associationsbetween all neonatal measures of vitamin D status [total - free 25(OH)D: beta coefficient (β) 6.10 (95% CI, 4.92,7.28)], total-bioavailable 25(OH)D: 6.48 (95% CI, 4.92,8.04)]. Maternal forms exhibited a similar patternof association, except for the bioavailable maternal form. In multivariate analysis, both total and free maternal 25(OH)D concentrations were correlated with all neonatal forms [neonatal total 25(OH)D: 1.29 (95% CI, 1.12,1.46) for maternal total 25(OH)D, 10.89 (8.16,13.63) for maternal free 25(OH)D], [neonatal free 25(OH)D: 0.15 for maternal total 25(OH)D, 1.28 (95% CI, 0.89,1.68) for maternal free 25(OH)D], and [0.13 (95% CI, 0.10, 0.16), 1.06 (95% CI, 0.68,1.43) for maternal free 25(OH)D], respectively, with the exclusion of the bioavailable maternal form.We observed no significant interactions within or between groups regarding maternal and neonatal vitamin D parameters and maternal calcium and parathyroid hormone concentrations, except for a borderline association between neonatal bioavailable 25(OH)D and albumin-adjusted neonatal calcium concentrations. Additionally, we found no significant association between maternal-neonatal vitamin D forms and neonatal birth anthropometry.Our study indicates that bioavailable maternal and neonatal 25(OH)D have no significant effects on vitamin D equilibrium, calcium homeostasis, and neonatal anthropometry at birth. However, we observed a remarkable biodynamic interaction between maternal and neonatal total and free 25(OH)D concentrations at the maternal-neonatal interface, with no associations observed with other calciotropic or anthropometric outcomes.




Cambridge University Press (CUP)

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Medicine and Health Sciences

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