Association of Protein and Vitamin D Intake With Biochemical Markers in Premature Osteopenic Infants: A Case-Control Study

Abstract

Osteopenia in preterm infants (OP) remains an important challenge and is largely dependent on nutritional post-natal intake of factors influencing bone mineralization. We conducted a prospective case-control study to evaluate the importance of protein and vitamin D intake in OP among neonates with birth weight <1,250 g. Simultaneous serum parathyroid hormone (PTH), alkaline phosphatase (ALP), calcium (Ca), phosphorus (P), vitamin D and protein levels were measured during the first six post-natal weeks. At 6 weeks of age, OP was evaluated using wrist radiographs. Comparisons were analyzed using multivariate linear regression, receiver operating characteristic curves, χ2 and Wilcoxon Rank Sum. Of the 26 premature infants enrolled, 13 developed radiographic OP. Daily protein intake (coef = −0.40, p = 0.001) and vitamin D concentrations (21 ± 5.7 ng/ml) were significantly lower in the OP group compared to non-OP subjects. ALP concentration exceeding 619 IU/L, sensitivity of 76.9% and specificity of 75%, was predictive of OP at 6 weeks post-natally. PTH levels were higher at 6 weeks in OP subjects (193 ± 102.5 pg/ml, p < 0.001) compared to non-OP subjects. The findings in this study support the role of vitamin D and protein intake in the development of OP in VLBW infants and inform future practice and research on best practices for OP management.

Catch it before it breaks!: managing metabolic bone disease of prematurity

“…Bone mineral density greater than 0.068 g/ cm 2 has been reported to be associated with a low risk of developing MBDP. However, DEXA imaging is complicated by limited availability, cost, and infant movement during the test, distorting the results [16,17].…”

“…necrotizing enterocolitis, bronchopulmonary dysplasia (BPD)] found in preterm infants [16]. Studies utilizing DEXA scans for evaluation of bone mineral content show that at 6 months of age, bone mineral content is often lower in preterm infants than in term infants and associated with poor postnatal growth from MBDP [16,17]. Xie et al showed that infants born at less than 29 weeks gestational age at birth were shorter and lighter than those born fullterm had lower bone mineral density (BMD) at the femoral neck in young adulthood (18-29 years of age).…”

“…The true incidence of fractures across all preterm infants with MBDP is currently unknown but is estimated to be 17-34% as most are incidental findings. Typically, the fractures occur in the long bones or the ribs [ More recent evidence has suggested that dualenergy x-ray absorptiometry (DEXA) imaging could be used to detect minute changes in bone mineral density and can predict the probability of fractures [16,17]. By assessing the probability of fractures, infants could be recognized as having fragile bones, which should influence care (e.g.…”

“…Studies have shown an inverse correlation with elevated ALP levels and low tibial z scores, which denote low bone density. Although not in common practice yet, this method might provide a preliminary screening for metabolic bone disease [16,18,20].…”

“…The American Academy of Pediatrics (AAP) Committee on Nutrition (AAP-CON) recommends screening all VLBW infants for MBDP starting at 4-5 weeks of age [7]. Despite the AAP recommendations and various studies showing the importance of some screening markers, there is no single uniform screening consensus [15][16][17][18][19]. This prevents clinicians from making the proper diagnosis and then instituting management of their metabolic bone disease.…”