title: Association between Vitamin D Receptor Polymorphism and Serum Vitamin D Levels in Children with Low-Energy Fractures.
abstract: Fractures of bones, especially forearm fractures, are very common in children and their number is increasing. This study was designed to determine the impact of vitamin D serum levels and vitamin D receptor (VDR) polymorphisms on the occurrence of low-energy fractures in children.
  
  
  
  The study group consisted of 100 children with clinically relevant bone fractures and a control group consisted of 127 children without fractures. Total vitamin D [25(OH)D3 plus 25(OH)D2] serum concentrations were evaluated in every patient. Genotypes for 4 restriction fragment length polymorphisms of the vitamin D receptor gene (FokI, ApaI, TaqI, and BsmI) were determined by standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques.
  
  
  
  Differences in concentrations of vitamin D were observed between the group with bone fractures (median = 12 ng/ml) and the control group (median = 16 ng/ml; p = 0.000044). Higher levels of vitamin D reduced the risk of fracture by 1.06 times (p = 0.0005). No impact of particular VDR polymorphism on the occurrence of low-energy fractures in children was detected. However, there were significant differences in the prevalence of FokI polymorphism genotypes between the fracture and control groups (p = 0.05). Furthermore, the recessive "aa" genotype of ApaI polymorphism and the dominant "TT" genotype of TaqI polymorphism were associated with higher levels of vitamin D (p = 0.005 and p = 0.036, respectively).
  
  
  
  Vitamin D deficiency is an independent risk factor for fractures in children. ApaI polymorphism recessive "aa" and TaqI polymorphism dominant "TT" genotypes are associated with higher levels of vitamin D in serum.
authors.affiliation: a Department of Pediatric Orthopedics and Traumatology , Medical University of Bialystok , Białystok , POLAND.
authors.forename: Michal
authors.initials: M
authors.lastname: Karpiński
authors.affiliation: b Department of Medical Chemistry , Medical University of Bialystok , Białystok , POLAND.
authors.forename: Anna
authors.initials: A
authors.lastname: Galicka
authors.affiliation: c Department of Statistics and Medical Informatics , Medical University of Bialystok , Białystok , POLAND.
authors.forename: Robert
authors.initials: R
authors.lastname: Milewski
authors.affiliation: a Department of Pediatric Orthopedics and Traumatology , Medical University of Bialystok , Białystok , POLAND.
authors.forename: Janusz
authors.initials: J
authors.lastname: Popko
authors.affiliation: d American Medical Holdings Inc. , Staten Island , New York.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Badmaev
authors.affiliation: e School of Pharmacy and Health Professions, Creighton University , Omaha , Nebraska.
authors.forename: Sidney J
authors.initials: SJ
authors.lastname: Stohs
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D050723:Fractures, Bone / Q000097:blood* / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D018167:Receptors, Calcitriol / Q000235:genetics*; D012307:Risk Factors; D014808:Vitamin D Deficiency / Q000235:genetics
chemical_list: D018167:Receptors, Calcitriol; C579457:VDR protein, human; D015652:25-Hydroxyvitamin D 2
keywords: 25-hydroxy-vitamin D; bone fractures; children; vitamin D deficiency; vitamin D receptor polymorphism