Determination of vitamin d and calcium metabolisms of term newborns and mothers and assesment of bone strength by quantitative ultrasound

Background and Aims: Vitamin D deficiency was reported in mothers living in urban parts of our country. Insufficient intake of vitamin D negatively effects bone mineralization and turnover. Changes in mothers bone turnover during pregnancy effects bone mineral composition of the fetus. The aim of this study was to evaluate the factors, biochemical markers and bone structure assessed by quantitative ultrasonography effecting vitamin D metabolism. Materials and Methods: Between January – November 2006, 90 term newborn and mothers included in the study which born in Celal Bayar University School of Medicine. Gestational age, birth weight, berth length, ponderel index, parity of the mothers, weight gain during pregnancy, smoking, alcohol and caffeine intake during pregnancy, vitamine supplementation were recorded. Serum levels of Ca, P, alkaline phosphatase (ALP), bone ALP (BALP), 1,25(OH)2D, 25(OH)D, parathyroid hormone (PTH), and osteocalcine levels were analyzed from the serums of mothers (during the postpartum first 4 days) and newborns (during the 4-10th days). Quantitative ultrasound from the tibial bone was performed for all infants during the first 96 hours and speed of sound (SOS) and Z scores were recorded. Results: Mean values for 25(OH)D (218.5±74.9) and 1,25(OH)2D (85.3±34,8) were within normal ranges in mothers. Significant correlations were observed between mothers 25(OH)D and newborns PTH and 25(OH)D levels. Serum 25(OH)D values were high in mothers who administered vitamin D supplementation (p=0.02), PTH values were high and osteocalcine values were low in mothers who did not used vitamin D supplementation (p=0.02 and p=0.03, respectively). PTH values were low in newborns whose mothers did not received vitamin D supplementation (p=0.004). SOS values of newborns were 3127±107 (range, 2900-3389), and mean Z scores were 0.3±0.7 (range, -1.4 - 2.6) which were determined by quantitative ultrasonography. Significant correlation was observed between the SOS scores and Ca and ALP values of the newborns (R=0.316, p=0.005 and R=-0.356, p=0.002; respectively). SOS scores of newbors whose mothers consumed caffeine products during pregnancy were lower than newborns whose mothers did not consumed caffeine products (3088±85 and 3187±112; respectively) (p=0.022). 1,23(OH)2D, 25(OH)D, and Ca levels were lower in mothers of newborns whose 25(OH)D levels were lower comparde to normal ones. No significant difference was observed for SOS and Z scores. Conclusion: Vitamin D values of the mothers and biochemical bone markers, vitamin D values and SOS values, which were assessed by quantitative ultrasound, of the newborns were within normal range in our region. Sufficient vitamin supplementation and nutrition of the mothers during pregnancy may prevent newborn osteopeny. Assessment of the structure of bone with quantitative ultrasound is a noninvasive and practical method.