In preterm infants, in whom perinatal mineralisation deficits are common, there is little information on long-term bone mineralisation. Using a Hologic QDR 1000 dual energy X-ray absorptiometer, bone mineral content and density (BMC and BMD) were measured in lumbar, spine, forearm and hip in 46 ex- preterm infants <32 weeks gestation together with controls at 8 years of age. Height and weight were recorded, as was history of bone fracture. Preterm infants were shorter by 4.9 cm (95% CI, 2.4 7.3) and lighter by 2.6 kg (95% CI, 0.7 4.4). BMC for all sites measured was significantly lower in the preterm group, but did not remain so when adjusted for height and weight. BMD was significantly reduced in the hip of the preterm group. Prolonged ventilation was associated with the lowest BMC and duration of preterm formula feeding correlated with higher BMC. Accidental fractures were less common in the preterm group.
Conclusion: Ex preterm infants have significant reduction in bone mineral mass commensurate with their reduced growth and reduced bone mineral density in their hips.