Background There is little information in preterm infants on long term bono minoralisation.

Method Using an Hologic QDR 1000 scanner, bone density was measured in 46 preterm infants <32/40 gestation together with controls. Bone density was determined on the lumber spine, left wrist, and left hip. Anthropometric measurements were made on day of scan.

Results Patient and control groups were matched in terms of age and sex. Preterm infants were significantly shorter (p=0.006) by 3.73cm (95% CI, 0.9-6.39cm) and lighter (p=0.034) by 2.51kg (95% CI, 0.2-4.8kg). Bone mineral content (BMI) for hip, lumbar spine and midarm was significantly lower in the preterm group (p=0.004, p=0.008, and p=0.02 respectively). This was not significant when adjusted for height and weight. Prolonged ventilation was associated with the lowest BMC (p<0.05, and r<-0.46), and duration of preterm formula feeding correlated with higher BMC (p=0.008, r-0.42).

Conclusion Preterm babies are shorter and lighter than term controls and have smaller BMC. Follow up through puberty to adulthood is important as our findings would suggest a likely reduction in peak bone mass, with sicker infants at increased risk of poor mineralisation.