title: Interpretation of plasma PTH concentrations according to 25OHD status, gender, age, weight status, and calcium intake: importance of the reference values.
abstract: BACKGROUND
  Reference values for plasma PTH assessment were generally established on small samples of apparently healthy subjects, without considering their 25-hydroxyvitamin D (25OHD) status or other potential modifiers of PTH concentration.
  
  
  OBJECTIVE
  Our objective was to assess ranges of plasma PTH concentration in a large sample of adults, stratifying by 25OHD status, age, gender, weight status, and calcium intake.
  
  
  METHODS
  This cross-sectional survey is based on 1824 middle-aged Caucasian adults from the Supplémentation en Vitamines et Minéraux Antioxydants study (1994).
  
  
  METHODS
  Plasma PTH and 25OHD concentrations were measured by an electrochemoluminescent immunoassay. Extreme percentiles of plasma PTH concentrations were assessed specifically in subjects who had plasmatic values of 25OHD of 20 ng/mL or greater and 30 ng/mL or greater.
  
  
  RESULTS
  Among subjects with 25OHD status of 20 ng/mL or greater, the 97.5th percentile of plasma PTH concentration was 45.5 ng/L. By using this value as a reference, 5% of the subjects with plasma 25OHD less than 20 nmol/L had a high plasma PTH level, reflecting secondary hyperparathyroidism. Among vitamin D-replete subjects (25OHD status of 20 ng/mL or greater), the 97.5th percentile of plasma PTH was higher in overweight/obese subjects (51.9 vs 43.5 ng/L among normal weight subjects).
  
  
  CONCLUSIONS
  The reference value for plasma PTH defined in this vitamin D-replete population was far below the value currently provided by the manufacturer (65 ng/L) and varied according to overweight status. These results may contribute to improve the diagnosis of primary and secondary hyperparathyroidism and subsequent therapeutic indication.
authors: Sorbonne Paris Cité Research Center (M.T., M.D., M.M., E.K.-G., L.K.F., P.L.-M., N.D.-P., P.G., S.H., K.E.), Nutritional Epidemiology Research Team, INSERM Unité 557, Institut National de la Recherche Agronomique Unité 1125, Conservatoire National des Arts et Métiers, and INSERM Unité 698 (A.S., N.C.), Paris 13 University, F-93017 Bobigny, France; Department Biochemistry (A.S., N.C.), Jean Verdier Hospital, F-93143 Bondy, France; Department of Dermatology (D.M., K.E.), St André Hospital, F-33000 Bordeaux, France; Department of Public Health (S.H.), Avicenne Hospital, F-93009 Bobigny, France; and Department of Physiology (J.-C.S.), Necker Hospital (Assistance Publique-Hôpitaux de Paris), and INSERM Unité 845, F-75270 Paris, France.
authors: Mathilde
authors: M
authors: Touvier
authors: Mélanie
authors: M
authors: Deschasaux
authors: Marion
authors: M
authors: Montourcy
authors: Angela
authors: A
authors: Sutton
authors: Nathalie
authors: N
authors: Charnaux
authors: Emmanuelle
authors: E
authors: Kesse-Guyot
authors: Léopold K
authors: LK
authors: Fezeu
authors: Paule
authors: P
authors: Latino-Martel
authors: Nathalie
authors: N
authors: Druesne-Pecollo
authors: Denis
authors: D
authors: Malvy
authors: Pilar
authors: P
authors: Galan
authors: Serge
authors: S
authors: Hercberg
authors: Khaled
authors: K
authors: Ezzedine
authors: Jean-Claude
authors: JC
authors: Souberbielle
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001835:Body Weight / Q000502:physiology*; D002118:Calcium / Q000008:administration & dosage*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D003940:Diagnostic Techniques, Endocrine / Q000592:standards / Q000706:statistics & numerical data; D004435:Eating; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D010281:Parathyroid Hormone / Q000097:blood*; D012016:Reference Values; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium