Reference limits for osteocalcin in infancy and early childhood: A longitudinal birth cohort study

Area of Science:

• Pediatric Endocrinology
• Biochemistry
• Growth and Development

Background:

• Longitudinal serum osteocalcin variations in early childhood are not well-established.
• Osteocalcin is a key bone-forming hormone, but its dynamic changes during infancy and early childhood require elucidation.

Purpose of the Study:

• To establish age- and sex-specific reference limits for total serum osteocalcin from birth to five years.
• To investigate the influence of breastfeeding and gestational age on serum osteocalcin levels during early childhood.

Main Methods:

• Analysis of serum samples from 551 Swedish children at birth, 4, 12, 36, and 60 months of age.
• Measurement of total serum osteocalcin using the IDS-iSYS N-MID Osteocalcin assay.
• Collection of maternal, birth, anthropometric, and dietary data.

Main Results:

• Established sex- and age-specific reference limits for serum osteocalcin at five time points.
• Observed a wavelike pattern: low at birth, peaking in the first year, declining, and rising again by age five.
• Found lower gestational age associated with higher birth osteocalcin and ongoing breastfeeding associated with higher levels.

Conclusions:

• Serum osteocalcin exhibits a characteristic wavelike pattern throughout early childhood.
• Understanding this pattern and its associations with sex, breastfeeding, and gestational age is crucial for clinical interpretation.
• These findings provide a basis for future research on osteocalcin's role in pediatric bone health.