title: The association between hypovitaminosis D and pediatric allergic diseases: A Korean nationwide population-based study.
abstract: BACKGROUND
  There is still considerable disagreement regarding the role of vitamin D in the development or exacerbation of allergic diseases.
  
  
  OBJECTIVE
  To investigate the association between serum vitamin D levels and recent symptoms of allergic diseases in elementary schoolchildren.
  
  
  METHODS
  A nationwide cross-sectional survey was conducted in children ages 6-7 years from 45 randomly selected elementary schools. The presence of atopic dermatitis (AD) or asthma was defined as medical treatment of children for AD or asthma within 12 months of the survey. The presence of allergic rhinitis (AR) was defined as medical treatment for AR during the past 12 months and a positive skin test response. Current AD was defined as confirmed eczema on physical examination. Serum 25-hydroxyvitamin D (25[OH]D) was measured by chemiluminescent immunoassay.
  
  
  RESULTS
  Questionnaire data and blood samples were collected from 3720 children. The overall prevalence rates of vitamin D insufficiency (20-29 ng/mL) and deficiency (<20 ng/mL) were 64.0% and 18.4%, respectively. For a 1 ng/mL decrease in 25(OH)D, the adjusted odds ratio (aOR) for AR was 1.020 (95% confidence interval [CI], 1.002-1.040) and the aOR for current AD was 1.027 (95% CI, 1.006-1.047). For each 1 ng/mL decrease in 25(OH)D, the aOR for positive skin-prick test reactivity was 1.013 (95% CI, 1.000-1.027). No significant association between vitamin D level and the prevalence of asthma was observed.
  
  
  CONCLUSIONS
  A high prevalence of vitamin D deficiency and insufficiency was found in Korean elementary schoolchildren, and low vitamin D levels were associated with recent symptoms of AD and AR.
authors.affiliation: 3Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hea-Kyoung
authors.initials: HK
authors.lastname: Yang
authors.forename: Jaehee
authors.initials: J
authors.lastname: Choi
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Kim
authors.forename: So-Yeon
authors.initials: SY
authors.lastname: Lee
authors.forename: Yong Mean
authors.initials: YM
authors.lastname: Park
authors.forename: Man Yong
authors.initials: MY
authors.lastname: Han
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Myung-Il
authors.initials: MI
authors.lastname: Hahm
authors.forename: Yoomi
authors.initials: Y
authors.lastname: Chae
authors.forename: Kee-Jae
authors.initials: KJ
authors.lastname: Lee
authors.forename: Ho-Jang
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Kangmo
authors.initials: K
authors.lastname: Ahn
authors.forename: Jihyun
authors.initials: J
authors.lastname: Kim
mesh_terms: D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood* / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D016017:Odds Ratio; D011159:Population Surveillance; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012882:Skin Tests; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D