title: [Evaluation assessment of the cut-off point of vitamin D in the population older than 64 years old].
abstract: OBJECTIVE
  Serum 25(OH)D(3) is the best indicator of vitamin D status, although some controversy remains regarding "normal" and "abnormal" values. The objective was to identify the 25(OH)D(3) serum concentration threshold which allows to know the 25(OH)D(3) serum levels correlated to PTH(i) increase and to describe the prevalence of hypovitaminosis D.
  
  
  METHODS
  Cross-sectional population study in subjects over 64 years of age residing in the basic healthcare areas in our hospital's area of reference.
  
  
  RESULTS
  A total of 239 persons -mean age (standard deviation) 72 (5.4) years- were evaluated. Mean serum concentrations of 25(OH)D(3) and PTH(i) were 17 (7.5) ng/ml and 60.5 (26.1) pg/ml, respectively. 32% of the subjects showed an increase in the serum concentration of PTH(i) > 65 pg/ml. 96% of the cases with an increase in PTH(i) had serum concentrations of 25(OH)D(3) < or = 25.5 ng/ml. In 70% of the subjects, the serum concentration levels of 25(OH)D(3) ranged between 11 and 25 ng/ml and in 17% the levels of 25(OH)D(3) were lower than 10 ng/ml.
  
  
  CONCLUSIONS
  The normal ranges for our population could correspond to levels of 25(OH)D3 > or = 25 ng/ml, with a 95% of sensibility to detect secondary hyperparathyroidism.
authors.affiliation: Albada, Centro Sociosanitario, Barcelona, España. mvaqueiro@cspt.es
authors.forename: Montserrat
authors.initials: M
authors.lastname: Vaqueiro
authors.forename: Maria Lluïsa
authors.initials: ML
authors.lastname: Baré
authors.forename: Esperança
authors.initials: E
authors.lastname: Anton
authors.forename: Eulàlia
authors.initials: E
authors.lastname: Andreu
authors.forename: Carmen
authors.initials: C
authors.lastname: Gimeno
mesh_terms: D000368:Aged; D002112:Calcifediol / Q000097:blood*; D002391:Catchment Area, Health; D003430:Cross-Sectional Studies; D006801:Humans; D006961:Hyperparathyroidism / Q000175:diagnosis / Q000453:epidemiology*; D010281:Parathyroid Hormone / Q000097:blood*; D015995:Prevalence; D012016:Reference Values; D013030:Spain; D014808:Vitamin D Deficiency / Q000175:diagnosis / Q000453:epidemiology*
chemical_list: D010281:Parathyroid Hormone; D002112:Calcifediol