Bone mineral status in breast-fed infants: influence of vitamin D supplementation.

BACKGROUND/OBJECTIVES: To assess bone status using quantitative ultrasound (QUS) applied to the second metacarpus and to evaluate the influence of vitamin D supplementation on bone mineralization in exclusively breast-fed infants.

SUBJECTS/METHODS: Seventy seven healthy exclusively breast-fed infants aged < 12 months underwent QUS evaluation with QUS DBM Sonic Aurora IGEA (MO, Italy), which measures speed of sound (mcSoS) and bone transmission time (mcBTT). Z-scores for age and length were also considered. Infants were divided into two groups, considering vitamin D supplementation.

RESULTS: mcSoS and mcBTT were significantly lower in the group of breast-fed infants without vitamin D supplementation (respectively, P = 0.001 and P = 0.015). A statistically significant difference was also observed between the two groups for Z-scores of QUS parameters for age and length, with lower levels in infants not supplemented with vitamin D. Both mcSoS and mcBTT decline during the first year of life. mcSoS inversely correlated with weight at enrollment and BMI at enrollment.

CONCLUSIONS: Our data support the importance of vitamin D supplementation in exclusively breast-fed infants in the first period of life to provide an adequate bone development.