title: Vitamin D deficiency in Spain: a population-based cohort study.
abstract: BACKGROUND
  Vitamin D deficiency is common worldwide. No homogenous reference values have yet been established and no studies of values have been conducted in Spain involving a large number of participants.
  
  
  OBJECTIVE
  To study the population concentrations of vitamin D in a representative sample of the Spanish population.
  
  
  METHODS
  The study involved two cohorts from Spain, the Asturias study and the Pizarra study, which are two prospective, population-based studies involving 2260 participants. In 1262 subjects (age: 20-83 years) we studied 25-hydroxyvitamin D, intact parathyroid hormone (iPTH), calcium, phosphorus and creatinine.
  
  
  RESULTS
  The median population values of 25-hydroxyvitamin D and iPTH were 22.46 ng/ml and 42.29 pg/ml, respectively. The values of 25-hydroxyvitamin D were significantly higher in summer and correlated with age (β = -0.05 ± 0.01, P < 0.0001), creatinine (β = 6.42 ± 1.17, P < 0.0001) and iPTH (-0.07 ± 0.01, P < 0.0001), but not with calcium, phosphorus or sex. The increase in iPTH with age was seen whatever the values of 25-hydroxyvitamin D, and was greater in the older persons. The concentration of iPTH rose continuously with effect from 25-hydroxyvitamin D values below ≈30 ng/ml. Values above ≈35 ng/ml were associated with a significantly lower concentration of iPTH.
  
  
  CONCLUSIONS
  One-third (33.9%) of the Spanish population may be at risk for Vitamin D deficiency. The 25-hydroxyvitamin D values above 30 ng/ml can safely discard 'hyper PTH'. The increase in iPTH concentration is greater in older persons for similar values of 25-hydroxyvitamin D.
authors.affiliation: Servicio de Endocrinología y Nutrición, Hospital Regional Universitario Carlos Haya, Málaga, Spain. inmagonzalezmolero@hotmail.com
authors.forename: I
authors.initials: I
authors.lastname: González-Molero
authors.forename: S
authors.initials: S
authors.lastname: Morcillo
authors.forename: S
authors.initials: S
authors.lastname: Valdés
authors.forename: V
authors.initials: V
authors.lastname: Pérez-Valero
authors.forename: P
authors.initials: P
authors.lastname: Botas
authors.forename: E
authors.initials: E
authors.lastname: Delgado
authors.forename: D
authors.initials: D
authors.lastname: Hernández
authors.forename: G
authors.initials: G
authors.lastname: Olveira
authors.forename: G
authors.initials: G
authors.lastname: Rojo
authors.forename: C
authors.initials: C
authors.lastname: Gutierrez-Repiso
authors.forename: E
authors.initials: E
authors.lastname: Rubio-Martín
authors.forename: E
authors.initials: E
authors.lastname: Menéndez
authors.forename: F
authors.initials: F
authors.lastname: Soriguer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D015995:Prevalence; D012016:Reference Values; D012307:Risk Factors; D012621:Seasons; D013030:Spain / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; C104450:25-hydroxyvitamin D; D003404:Creatinine; D002118:Calcium