Mineral status of premature infants in early life and linear growth at age three.

Background Preterm infants are at significant risk of reduced bone mineral content and subsequent bone disease (metabolic bone disease of prematurity, MBDP). MBDP is frequently found in very low-birthweight (VLBW) infants, but long-term height prognosis is not well known. Methods VLBW infants from two major neonatal intensive care units were studied. Medical records were reviewed. A total of 143 subjects were analyzed after excluding subjects who died, or who had severe complications that could affect linear growth, Silver-Russell syndrome, severe cholestasis, and/or chromosomal abnormality. The relationship between MBDP and height at age 3 was investigated. Results Height standard deviation score (SDS) at age 3 negatively correlated with peak serum alkaline phosphatase (ALP) activity in early life (r=-0.30, P=0.0003) and positively correlated with serum phosphorus (P) at peak ALP (r=0.33, P=0.0002). In addition, serum P independently affected height SDS at 3 years of age (=0.19, P=0.018), and was significantly different between infants with and without catch-up growth in height (difference: 0.23mmol/L, 95%CI: 0.09-0.36, P=0.0010). Conclusions MBDP, particularly hypophosphatemia in the early period of life, is associated with linear growth until 3 years of age in VLBW infants.