Bone mass in First Nations, Asian and white newborn infants.

OBJECTIVE: To compare bone mass in newborn infants of First Nations, white and Asian mothers while accounting for vitamin D status. Fifty infants born healthy at term age were measured for bone mass using dual energy x-ray absorptiometry (DXA) within 15 days of life. Vitamin D status was measured as 25(OH)D in cord plasma. White infants were separated based on 25(OH)D concentrations into sufficient and insufficient (< 32.5 nmol/L) to match for vitamin D status of the Asian infants and the First Nations group. Differences among groups were tested using ANOVA and post hoc testing with Bonferroni multiple comparisons test. There were no differences in whole body, spine or femur BMC between the white sufficient and insufficient infants. However, the Asian infants had lower (P < 0.01) spine BMC compared to the white infants and the First Nations infants were intermediate. No differences among the ethnic groups were observed for whole body or femur BMC. These data suggest that white and First Nations newborn infants have comparable bone mass. Asian infants have lower spine bone mass which is more than a factor of body size and independent of vitamin D status at birth.