ASSESSMENT OF BONE MINERAL DENSITY AND MARKERS OF BONE TURNOVER IN CHILDREN UNDERGOING LONG-TERM ORAL ANTICOAGULANT THERAPY
INTRODUCTION: Oral anticoagulants antagonize vitamin K action and potentially impair the carboxylation of osteocalcin, a protein that is essential for normal bone matrix formation.
OBJECTIVE: Our aim was to evaluate bone mineral density (BMD) and bone-turnover markers in 23 children who were undergoing long-term oral anticoagulant therapy (median age: 4 years) and 25 age- and gender-matched controls.
METHODS: BMD (characterized as a z score) of the lumbar spine was assessed by using dual energy radiograph absorptiometry. Osteoblast (bone alkaline phosphatase, osteocalcin, and amino-terminal procollagen 1 extension peptide) and osteoclast (urinary calcium and deoxypyridinoline and serum cross-linked C telopeptide) activity markers were measured. Vitamin D (25-hydroxy vitamin D, parathyroid hormone, whole and ionized calcium, phosphorus, and magnesium) and vitamin K (factors II, VII, IX, and X, protein C, protein S, and undercarboxylated osteocalcin [Glu-Oc]) statuses were determined.
RESULTS: Patients presented with higher levels of Glu-Oc, parathyroid hormone, and bone-resorption markers and lower levels of bone-formation markers and 25-hydroxy vitamin D; 52% of them showed signs of osteopenia (−1.0 > BMD z score > −2.5). Statistical analysis demonstrated that anticoagulant therapy was an independent predictor of alterations in Glu-OC, osteocalcin, bone alkaline phosphatase, amino-terminal procollagen 1 extension peptide, and serum cross-linked C telopeptide levels.
CONCLUSIONS: Long-term use of coumarin derivatives may cause osteopenia in children with the risk of developing osteoporosis later in life.
Submitted by Maria Avgeri
- Copyright © 2008 by the American Academy of Pediatrics