The Long-Term Impact of Preterm Birth on Metabolic Bone Profile and Bone Mineral Density in Childhood

Background/Objectives: Recent data on long-term consequences of prematurity on bone health are conflicting. The aim of this study was to assess the metabolic bone profile and bone mineral density (BMD) in prepubertal children born prematurely and to examine possible associations between bone health parameters and perinatal morbidity factors. Methods: This cross-sectional observational study included 144 children of mean (SD) age 10.9 (1.6) years: 49 children born very preterm (≤32 gestational weeks), 37 moderate-to-late preterm (32⁺¹ to 36⁺⁶ gestational weeks), and 58 born at term (controls). Serum levels of calcium/Ca, phosphorus/P, alkaline phosphatase/ALP, 25-hydroxyvitamin D/25(OH)D, bone formation markers (osteocalcin/OC, procollagen type I C-terminal propeptide/PICP, and insulin growth factor-1/IGF-1), and bone resorption markers (serum tartrate-resistant acid phosphatase 5b/bone TRAP5band urinary calcium-to-creatinine ratio) were measured. Total-body and lumbar-spine BMD and BMD Z-scores were calculated using dual-energy X-ray absorptiometry/DXA. Results: Children born very preterm showed significantly higher ALP, OC, PICP, and bone TRAP5b levels compared to controls, as well as compared to children born moderate-to-late preterm. Total-body and lumbar-spine BMD Z-scores were significantly lower in the very preterm-born group compared to controls. Gestational diabetes, preeclampsia, and bronchopulmonary dysplasia were associated with lower total-body BMD in the very preterm-born population. Conclusions: Preterm birth is associated with impaired metabolic bone profile and lower total-body and lumbar-spine BMD in childhood. Moderate-to-late preterm-born children exhibit altered metabolic bone parameters compared to very preterm-born children. Further research in children might allow better insight into the long-term impact of preterm birth on bone health.