The Clinical and Biochemical Predictors of Bone Mass in Preterm Infants.

Metabolic bone disease of prematurity still occurs in preterm infants, although a significant improvement in neonatal care has been observed in recent decades. Dual-energy X-ray absorptiometry (DXA) is the precise technique for assessing bone mineral content (BMC) in preterm infants, but is not widely available.To investigate the clinical and biochemical parameters, including bone metabolism markers as potential predictors of BMC, in preterm infants up to 3 months corrected age (CA).Ca-P homeostasis, iPTH, 25-hydroxyvitamin D, osteocalcin, N-terminal propeptide, cross-linked C-telopeptide and amino-terminal pro C-type natriuretic peptide and the DXA scans were prospectively performed in 184 preterm infants (≤ 34 weeks' gestation) between term age and 3 mo CA. Lower bone mass was defined as BMC below or equal to respective median value for the whole study group, rounded to the nearest whole number.The appropriate quality DXA scans were available for 160 infants (87%) examined at term and for 130 (71%) tested at 3 mo CA. Higher iPTH level was the only independent predictor of lower BMC at term, whereas lower BMC at 3 mo CA was associated both with lower urinary phosphate excretion and higher serum osteocalcin level. ROC analysis showed that iPTH >43.6 pg/mL provided 40% sensitivity and 88% specificity in identification of preterm infants with lower BMC at term. In turn, urinary phosphate excretion (TRP>97% or UP/Cr ≤0.74 mg/mg) and serum osteocalcin >172 ng/mL provided 40% sensitivity and 93% specificity in identification of infants with decreased BMC at 3 mo CA.Serum iPTH might to be a simple predictor of reduced BMC in preterm infants at term age, but urinary phosphate excretion and serum osteocalcin might predict reduced BMC at 3 mo CA. These results represent a promising diagnostic tool based on simple, widely available biochemical measurements for bone mass assessment in preterm infants

Impact of Vitamin D Supplementation during Lactation on Vitamin D Status and Body Composition of Mother-Infant Pairs: A MAVID Randomized Controlled Trial

<div><p>Objective</p><p>The optimal vitamin D intake for nursing women is controversial. Deterioration, at least in bone mass, is reported during lactation. This study evaluated whether vitamin D supplementation during lactation enhances the maternal and infant’s vitamin D status, bone mass and body composition.</p><p>Design and Methods</p><p>After term delivery, 174 healthy mothers were randomized to receive 1200 IU/d (800 IU/d+400 IU/d from multivitamins) or 400 IU/d (placebo+400 IU/d from multivitamins) of cholecalciferol for 6 months while breastfeeding. All infants received 400 IU/d of cholecalciferol. Serum 25-hydroxyvitamin D [25(OH)D], iPTH, calcium, urinary calcium, and densitometry were performed in mother-offspring pairs after delivery, and at 3 and 6 months later.</p><p>Results</p><p>A total of 137 (79%) (n = 70; 1200 IU/d, n = 67; 400 IU/d) completed the study. 25(OH)D was similar in both groups at baseline (13.7 ng/ml vs. 16.1 ng/ml; <i>P = </i>0.09) and at 3 months (25.7 ng/ml vs. 24.5 ng/ml; <i>P</i> = 0.09), but appeared higher in the 1200 IU/d group at 6 months of supplementation (25.6 ng/ml vs. 23.1 ng/ml; <i>P</i> = 0.009). The prevalence of 25(OH)D <20 ng/ml was comparable between groups at baseline (71% vs. 64%, <i>P</i> = 0.36) but lower in the 1200 IU/d group after 3 months (9% vs. 25%, <i>P</i> = 0.009) and 6 months (14% vs. 30%, <i>P</i> = 0.03). Maternal and infants’ iPTH, calciuria, bone mass and body composition as well as infants’ 25(OH)D levels were not significantly different between groups during the study. Significant negative correlations were noted between maternal 25(OH)D and fat mass (R = −0.49, <i>P</i> = 0.00001), android fat mass (R = −0.53, <i>P</i> = 0.00001), and gynoid fat mass (R = −0.43, <i>P</i> = 0.00001) after 6 months of supplementation.</p><p>Conclusions</p><p>Vitamin D supplementation at a dose of 400 IU/d was not sufficient to maintain 25(OH)D >20 ng/ml in nursing women, while 1200 IU/d appeared more effective, but had no effect on breastfed offspring vitamin D status, or changes in the bone mass and the body composition observed in both during breastfeeding.</p><p>Trial Registration</p><p>ClinicalTrials.gov <a href="http://clinicaltrials.gov/" target="_blank">NCT01506557</a></p></div

Maternal anthropometry and body composition throughout the study.

<p>Data presented as median (interquartile range: Q1–Q3). No significant differences between groups, all <i>P-value></i>0.05. (<i>BMD -</i> bone mineral density, less head BMD - total body less head mineral density, BMC -bone mineral content, less head BMC - total body less head mineral content, LBM - total lean body mass, BMI - body mass index, FM- total fat, android FM – android fat mass, gynoid FM – gynoid fat mass).</p><p>Maternal anthropometry and body composition throughout the study.</p

Comparison of ITT population with participants lost to follow-up.

<p>Data are presented as median and interquartile range (Q1–Q3) or number and (%). <i>P-value</i><0.05 are highlighted.</p><p>Comparison of ITT population with participants lost to follow-up.</p

Vitamin D intake, sun exposure, and compliance.

<p>Data are presented as median and interquartile range (Q1–Q3) or number and (%). <i>P-value</i><0.05 are highlighted.</p><p>Vitamin D intake, sun exposure, and compliance.</p

Maternal (A) and infants’ (B) vitamin D status.

<p>Percentage of participants with serum 25(OH)D level <20 ng/ml, 20–29.9 ng/ml and >30 ng/ml in both study groups (maternal vitamin D intake 400 IU/d vs. 1200 IU/d). Significant (<i>P<0.05</i>) differences between the study groups are shown on the figures.</p

Infants’ anthropometry and body composition throughout the study.

<p>Data presented as median (interquartile range: Q1–Q3). No significant differences between groups, all <i>P-value></i>0.05. (Δ - increment (change) of the study variable between baseline and next visit, <i>BMD -</i> bone mineral density, less head BMD - total body less head mineral density, BMC - bone mineral content, less head BMC - total body less head mineral content, LBM - total lean body mass, BMI - body mass index, FM - total fat, android FM – android fat mass, gynoid FM – gynoid fat mass).</p><p>Infants’ anthropometry and body composition throughout the study.</p

Sociodemographic and clinical characteristics of the mothers and infants at study enrollment based on vitamin D supplementation group.

<p>Data are presented as median and interquartile range (Q1–Q3) or number and (%). <i>P-value</i><0.05 are highlighted.</p><p>Sociodemographic and clinical characteristics of the mothers and infants at study enrollment based on vitamin D supplementation group.</p