Background: Maximum bone mass accretion in the fetal skeleton is acquired during the third trimester of gestation, and may be compromised in premature newborns.
Objective: To ascertain the incidence and evolution of osteopenia, a longitudinal study was performed to evaluate areal bone mineral density (aBMD) in the lumbar spine in premature newborns followed during the first 2 years of life.
Methods: aBMD values were assessed in lumbar spine (L2-L4) by DEXA and expressed as grams hydroxyapatite/cm2 in 80 premature newborns, 41 boys and 39 girls, of gestational ages 24.5-35.7 weeks. aBMD values were evaluated at (mean+/-SD) 0.2+/-0.1 years (at discharge from the neonatal unit), 0.9+/-0.2 years and 2.0+/-0.5 years of postnatal age, and compared with those of age- and sex-matched full-term newborns with normal intrauterine and postnatal growth.
Results: aBMD values recovered progressively from the first to the third evaluations, and were 0.139+/-0.06 g/cm2 (-2.4+/-1.4 SDS) at 0.2+/-0.1, 0.270+/-0.06 g/cm2 (-1.0+/-1.0 SDS) at 0.9+/-0.2 and 0.410 g/cm2 (-0.08+/-1.0 SDS) at 2.0+/-0.5 years.
Conclusions: Our data show a significant catch-up of aBMD, reaching values similar to those of full-term newborns at the age of 0.2+/-0.5 years, regardless of the gestational age at birth.