title: Vitamin D deficiency in children aged 6 to 12 years: single center's experience in Busan.
abstract: OBJECTIVE
  This study investigated the prevalence and risk factors associated with vitamin D deficiency in children.
  
  
  METHODS
  We analyzed the medical records of 330 patients from the age of 6 to 12, who visited the endocrinology clinic of the Department of Pediatrics at Pusan National University Hospital, from September, 2013 to May, 2014. According to their serum 25-hydroxyvitamin D (25(OH)D) levels, the patients were grouped into either the deficiency group (25(OH)D<20 ng/mL), or the sufficiency group (25(OH)D≥20 ng/mL). The differences between the 2 groups were compared.
  
  
  RESULTS
  There were 195 patients (59.1%) who had vitamin D deficiency. Their mean serum 25(OH)D level was 14.86±3.20 ng/mL. The differences in sex, age, and pubertal status between the 2 groups were not statistically significant. Weight standard deviation score (SDS), and body mass index SDS, were significantly higher in the vitamin D deficiency group (P=0.002 for each), compared to the sufficiency group. Compared with Autumn, both Spring (odds ratio [OR], 9.7; 95% confidence interval [CI], 4.3-22.0), and Winter (OR, 5.9; 95% CI, 3.5-10.0), were risk factors for vitamin D deficiency. In multiple logistic regression analysis, only seasonal differences have been confirmed to have an effect on vitamin D deficiency.
  
  
  CONCLUSIONS
  Vitamin D deficiency in children aged 6 to 12 years is very common. Spring and Winter are the most important risk factors for vitamin D deficiency. We suggest that it is necessary to supplement the guideline for the vitamin D intake according to our situation.
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Young Eun
authors: YE
authors: Roh
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Bo Ryung
authors: BR
authors: Kim
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Won Bok
authors: WB
authors: Choi
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Young Mi
authors: YM
authors: Kim
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Min-Jung
authors: MJ
authors: Cho
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Hye-Young
authors: HY
authors: Kim
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Kyung Hee
authors: KH
authors: Park
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Kwang Hoon
authors: KH
authors: Kim
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Peter
authors: P
authors: Chun
authors: Department of Pediatrics, Pusan National University Children's Hospital, Pusan National University School of Medicine, Yangsan, Korea.
authors: Su Young
authors: SY
authors: Kim
authors: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
authors: Min Jung
authors: MJ
authors: Kwak
keywords: Child; Prevalence; Risk factors; Vitamin D deficiency