title: Estimation of the cutoff value of vitamin D: the Dong-gu study.
abstract: BACKGROUND
  Vitamin D plays an essential role in bone health and growth, but the optimal serum 25-hydroxyvitamin D (25(OH)D) concentration is not known. This study was performed to investigate the optimal 25(OH)D concentration in regard to parathyroid hormone (PTH) concentration in the Korean general population aged 50 years or older.
  
  
  RESULTS
  The study population consisted of 8,857 subjects (3,545 men and 5,312 women) who participated in the baseline survey of the Dong-gu study, conducted in Korea between 2007 and 2010. Serum 25(OH)D and PTH concentrations were measured by chemiluminescent microparticle immunoassay. The optimal 25(OH)D concentration was estimated by using nonlinear regression model. Our data show that PTH concentration reached a theoretical plateau at 38.2 pg/ml and corresponding 25(OH)D concentration was 21.1 ng/ml in men and PTH concentration at 42.9 pg/ml and 25(OH)D concentration at 13.8 ng/ml in women.
  
  
  CONCLUSIONS
  These results indicate that, for Korean general population aged 50 years or older, the optimal 25(OH)D concentration is 21.1 ng/ml in men and 13.8 ng/ml in women.
authors: Seong-Woo
authors: SW
authors: Choi
authors: Sun-Seog
authors: SS
authors: Kweon
authors: Jin-Su
authors: JS
authors: Choi
authors: Jung-Ae
authors: JA
authors: Rhee
authors: Young-Hoon
authors: YH
authors: Lee
authors: Hae-Sung
authors: HS
authors: Nam
authors: Seul-Ki
authors: SK
authors: Jeong
authors: Kyeong-Soo
authors: KS
authors: Park
authors: So-Yeon
authors: SY
authors: Ryu
authors: Hye-Rim
authors: HR
authors: Song
authors: Min-Ho
authors: MH
authors: Shin
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D012016:Reference Values; D056910:Republic of Korea / Q000453:epidemiology; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D