[1] Linkoping Univ, Dept Clin Chem, SE-58185 Linkoping, Sweden
[2] Linkoping Univ, Dept Clin & Expt Med, SE-58185 Linkoping, Sweden
[3] Robert Jones & Agnes Hunt Orthopaed Hosp, Charles Salt Ctr Human Metab, Oswestry SY10 7AG, Shrops, England
[4] Obafemi Awolowo Univ, Coll Hlth Sci, Dept Orthopaed Surg & Traumatol, Ife, Nigeria