ESPE Abstracts

Context: Osteocalcin is a bone formation marker that has recently sparked interest for its endocrine involvement in glucose homeostasis and obesity. Nevertheless, its natural pattern during infancy and early childhood remains unknown.

Objectives: We established reference values for total serum osteocalcin during specific timepoints from birth until five years of age, and presented these in the context of covariates.

Methods: Blood samples from the umbilical cord, and 4, 12, 36 and 60 months of age together with information about the mother, birth, anthropometrics, and a food diary were retrieved for a longitudinal birth cohort in Sweden.

Results: Gender- and age-specific reference values were established for the specified timepoints. Osteocalcin displayed a wave-like pattern over time, with low levels in the umbilical cord, a postnatal peak during the first year, and a decline thereafter that rose again by the age of five. Median osteocalcin levels were 43.7 - 91.0 - 68.9 - 61.6 - 79.7ng/ml for boys and 37.6 – 100.0 – 81.7 – 70.5 - 93.1ng/ml for girls. Gestational age, size for gestational age, breastfeeding practices, and growth influenced early osteocalcin values.

Conclusion: We suggest that osteocalcin follows a specific pattern, with high levels preceding the infancy BMI peak. Since covariates (e.g. sex, breastfeeding and size for gestational age) may impact the amplitude and/or the tempo along this pattern, osteocalcin levels should be interpreted with regards to these factors.