title: Risk factors for low vitamin D status in Korean adolescents: the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2009.
abstract: OBJECTIVE
  To evaluate the prevalence of vitamin D deficiency and predictors for low vitamin D status in Korean adolescents living between latitudes 33° and 39° N.
  
  
  METHODS
  A descriptive cross-sectional study.
  
  
  METHODS
  Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2009.
  
  
  METHODS
  A total of 1510 healthy adolescents aged 12-18 years (806 male, mean age 14.7 years) participated. Possible predictors for low vitamin D status (log-transformed 25-hydroxyvitamin D (25(OH)D) concentrations) were evaluated.
  
  
  RESULTS
  The prevalence of vitamin D deficiency (25(OH)D<20 ng/ml) was 89.1% in spring, 53.7% in summer, 63.9% in autumn and 90.5% in winter. Winter season, older age, higher education level reached, being female, being obese, a lack of vitamin D supplementation, lower milk consumption (0-<200 ml/d) and a lack of physical activity were unadjusted predictors (all P < 0.05). Multiple linear regression analysis showed that winter season (P < 0.001), higher education level (P < 0.001) and a lack of vitamin D supplementation (P = 0.012) were independent predictors for low vitamin D status. The modifying effect of season on the association between vitamin D supplement use and vitamin D status was significant (P < 0.001).
  
  
  CONCLUSIONS
  Vitamin D deficiency was highly prevalent in Korean adolescents, especially those in higher school grades. Vitamin D supplementation may contribute to maintain a better vitamin D status with lower seasonal variation. Further studies are required to determine optimal vitamin D intakes to maintain sufficient vitamin D status for Korean adolescents.
authors: 1 Division of Endocrinology and Metabolism, Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-769, Republic of Korea.
authors: Young Ah
authors: YA
authors: Lee
authors: 1 Division of Endocrinology and Metabolism, Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-769, Republic of Korea.
authors: Hwa Young
authors: HY
authors: Kim
authors: 2 Medical Research Collaborating Center, Seoul National University Hospital, Seoul, Republic of Korea.
authors: Hyunsook
authors: H
authors: Hong
authors: 1 Division of Endocrinology and Metabolism, Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-769, Republic of Korea.
authors: Ji Young
authors: JY
authors: Kim
authors: 3 Health and Exercise Science, Institute of Sports Science, Seoul National University, Seoul, Republic of Korea.
authors: Hyun Jin
authors: HJ
authors: Kwon
authors: 1 Division of Endocrinology and Metabolism, Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-769, Republic of Korea.
authors: Choong Ho
authors: CH
authors: Shin
authors: 1 Division of Endocrinology and Metabolism, Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-769, Republic of Korea.
authors: Sei Won
authors: SW
authors: Yang
mesh_terms: D000293:Adolescent; D044466:Asian People; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D009043:Motor Activity; D009749:Nutrition Surveys; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012621:Seasons; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014807:Vitamin D