Determinants of bone mass and size in 7-year-old former term, late-preterm, and preterm boys.

UNLABELLED: When compared, full-term prepubertal boys had greater regional bone size, higher total body (TB) bone mineral content (BMC), and regional bone density than preterm boys but higher TB bone content area and regional BMC than late-preterm boys. Implications include follow-up bone assessment and preterm formula feeding in late-preterm boys.

INTRODUCTION

This study was conducted to determine whether there are differences in bone mass and size among prepubertal boys born preterm (PT; < or =34 weeks gestation), late-preterm (LP; >34 and < or =37 weeks gestation), and at term (>37 weeks gestation) and to identify factors that are associated with bone mass and size in these children.

METHODS

Total body (TB), spine and hip dual energy X-ray absorptiometry and tibia peripheral quantitative computed tomography measures were obtained on 24 boys aged 5.7 to 8.3 years.

RESULTS

In multiple regression analysis adjusting for current weight, height, age, and jump power, term boys had greater cortical thickness (p = 0.03) and area (p = 0.01), higher trabecular volumetric bone mineral density (p = 0.05), TB bone mineral content (BMC; p = 0.007), and hip areal bone mineral density (aBMD; p = 0.01) than PT boys, and higher TB BMC (p = 0.01), TB bone area (p = 0.03), hip BMC (p = 0.02) and aBMD (p = 0.01), and femoral neck BMC (p = 0.05) and aBMD (p = 0.02) than LP boys. There were no differences in activity measures among gestation groups and no group-by-activity interactions.

CONCLUSION

Term boys have greater bone size and mass than PT boys and higher bone mass than LP boys at several bone sites. Activity measures did not differ among gestation groups and did not explain bone differences.