title: [Relationship between serum 25-hydroxyvitamin D and bone mineral density in children under 7 years old].
abstract: OBJECTIVE
  To evaluate the endogenous vitamin D level and its correlation with bone mineral density (BMD) in children under 7 years old.
  
  
  METHODS
  Totally 6 838 children who visited the Growth and Development Clinic due to "growth retardation, night terrors, hyperhidrosis, and dysphoria" were enrolled in the study. Serum 25-hydroxyvitamin D [25(OH)D] level was measured by chemiluminescence, whereas individual BMD was measured by quantitative ultrasound.
  
  
  RESULTS
  Among all subjects, serum 25(OH)D level was 34 ± 14 ng/mL, and the Z value of BMD was -0.49 ± 0.54. With increasing age, serum 25(OH)D level and BMD decreased gradually (P<0.01), and the detection rates for vitamin D deficiency and low BMD increased gradually (P<0.01). Compared with those with sufficient vitamin D, children with vitamin D deficiency had a significantly lower BMD (P<0.01) and a significantly higher detection rate for low BMD (P<0.01). 25-(OH)D level showed a positive linear correlation with BMD in children with vitamin D deficiency (P<0.01).
  
  
  CONCLUSIONS
  Preschool and school-age children have severer vitamin D deficiency than infants. Vitamin D level may be correlated with BMD within a certain range.
authors.affiliation: Department of Pediatrics, West China Second University Hospital, Chengdu 610041, China. xiongfei7922.student@sina.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Xiong
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Su-Fei
authors.initials: SF
authors.lastname: Yang
authors.forename: Kang-Min
authors.initials: KM
authors.lastname: Wu
mesh_terms: D015519:Bone Density; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D