Growth and bone mineralization in children born prematurely

Objective: To study the growth and bone mineralization of children born prematurely. Study Design: A cohort of healthy children who were born prematurely with birth weight less than 1.5 kg were compared by weight and height to a national reference. Bone mineral status of preterm infants was compared with children who were born at term gestation. The average follow-up was 7 years. A sample of children who were born prematurely was recalled from an infant nutrition study. Children born at term gestation who had similar body weight for age were recruited from the community. Bone mineral evaluation was conducted in a group of 20 children born prematurely with birth weight less than 1.5 kg and in 15 children born at term gestation. Body weight for age was similar between the groups. All children were born of appropriate size for gestational age at birth. All children had their body weight and height measured. Comparisons for growth assessment status were made with the NHANES III database and published standards. Dietary intakes and food frequency were analyzed. The bone mineral status was measured at two sites, lumbar spine and distal third radius bone. Results: The average age was 7 years, with a range of 5 to 9 years. Compared with the reference population, children who were born prematurely on the average had lower weights, heights and body mass index. Preterm children had a lower lumbar bone mineral content than term children, 12.8 +/- 3.0 and 14.7 +/- 2.2g cm(-1) (P < 0.05). The lumbar bone mineral density was lower in the preterm group than in the term group, 0.525 +/- 0.062 and 0.574 +/- 0.073 g cm(-2), respectively (P < 0.04). Three of the preterm children had a history of fracture whereas none of the term children reported any fractures. Conclusion: Children who were born prematurely with birth weights less than 1.5 kg tend to be significantly smaller for age and have lower lumbar spinal bone mineral content and density compared with children born at term gestation.