Pronounced elevation of undercarboxylated osteocalcin in healthy children

Pediatr Res. 2007 Mar;61(3):366-70. doi: 10.1203/pdr.0b013e318030d0b1.


The vitamin K-dependent protein osteocalcin is thought to play an important role in bone metabolism. Osteocalcin contains glutamic acid (Gla) residues, which have a high affinity for calcium. Vitamin K acts as an indispensable cofactor for the formation of these residues. Inadequate dietary vitamin K intake results in the synthesis of undercarboxylated (i.e. inactive) osteocalcin (ucOC). In adults, low vitamin K status of bone is associated with low bone density and increased risk of osteoporotic fractures. Little is known about vitamin K status and bone health in children. We used a cross-sectional study design to compare the vitamin K status of bone in healthy children (n = 86) with that of adults (n = 30). In children, a marked elevation of the ratio of ucOC/carboxylated osteocalcin (cOC), indicative of a poor vitamin K status, was observed. This difference persisted after adjusting for age, gender, puberty, height, weight. Furthermore, a marked correlation between the bone markers for bone metabolism and ucOC and cOC was found in the children's group. These findings suggest a pronounced low vitamin K status of bone during growth. The question remains, however, whether children would benefit from higher vitamin K intake, for instance, by improved bone health or stronger bones.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Bone and Bones / metabolism
  • Carboxylic Acids / chemistry
  • Child
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Osteocalcin / blood*
  • Osteocalcin / chemistry
  • Reference Values
  • Vitamin K / administration & dosage
  • Vitamin K / metabolism


  • Carboxylic Acids
  • Osteocalcin
  • Vitamin K