Developmental Osteopenia: An Explanation for Fractures in Young Infants

AIM: The aim is to test whether a fraction of full-term infants pass through a phase of postnatal fracture susceptibility and whether this physiological phase explains real-world fracture age distributions in young infants. METHODS: Preterm infant data were used to establish fracture risk zones based on bone quality (using Speed of Sound, SOS) and metabolic activity (Alkaline Phosphatase, ALP) levels. These reference thresholds were applied to a full-term cohort to identify clinical overlap. Age distributions of full-term infants within risk zones were evaluated alongside paediatric fracture data from the KID Inpatient Database and data concerning rib fractures from cardiopulmonary resuscitation (CPR). RESULTS: The low-SOS and high-ALP tails of the full-term population overlap with risk zones for metabolic bone disease of prematurity (MBDP) during the post-birth trough in bone mineralisation. The log-normal age distributions of full-term infants in these risk zones are indicative of a developmental phase and share the morphology and peak timing of infant rib and multiple fractures, whether registered as abuse, accidental, or CPR-related. CONCLUSION: The synchronisation of fracture peaks with the physiological trough of infant bone quality supports Developmental Osteopenia as an explanatory framework for rib and multiple fractures in young infancy.