Determinants of bone mineral content in preterm neonates

Objectives: The objective of the study was to quantify total body less head (TBLH) bone mineral content (BMC) at 6 weeks in preterm neonates and identify clinical and nutritional determinants. Material and Methods: Preterm infants born ≤33 weeks underwent dual-energy x-ray absorptiometry (DXA) scan (Lunar GE DPX) at 6 weeks of age. Perinatal variables, neonatal intensive care unit course, and biochemistry were recorded. Correlations and linear regression identified independent predictors of BMC. Results: Forty-four neonates were analyzed (gestation 29.8 ± 1.7 weeks; birth weight 1158.2 ± 293.2 g). Mean TBLH BMC and BMD were 15.0 ± 6.4 g and 0.52 ± 0.07 g/cm 2 , respectively. BMC correlated positively with gestation (r = 0.65), birth weight (r = 0.77), birth length (r = 0.82), calcium (r = 0.37), and phosphorus (r = 0.64), and inversely with ALP (r = −0.65), total parenteral nutrition (TPN) duration (r = −0.72), and ventilation duration (r = −0.50) (all P ≤ 0.01). In multivariable analysis, birth length (β = 0.52; 95% CI = 0.20–0.84; P = 0.01), TPN duration (β = −0.70; 95% CI = −1.20–−0.20; P = 0.001), ventilation duration (β = −0.57; 95% CI = −0.92– −0.22; P = 0.002), and fortification delay (β = −0.48; 95% CI = −0.80–−0.16; P = 0.002) independently predicted BMC (R 2 = 0.768). A 1-week prolongation of TPN or ventilation was associated with BMC reductions of ~3.85 g and ~2.0 g, respectively, advancing fortification by a week increased BMC by ~3.7 g. Conclusion: Prolonged TPN, ventilation, and delayed fortification are modifiable determinants of BMC in preterm neonates. Early enteral optimization and timely fortification may improve skeletal outcomes.