title: Reference values for TSH may be inadequate to define hypothyroidism in persons with morbid obesity: Di@bet.es study.
abstract: To analyze the reference range of thyroid-stimulating hormone (TSH) in different BMI categories and its impact on the classification of hypothyroidism.
  
  
  
  The study included 3,928 individuals free of thyroid disease (without previous thyroid disease, no interfering medications, TSH <10 µUI/mL and thyroid peroxidase antibodies [TPO Abs] <50 IU/mL) who participated in a national, cross-sectional, population-based study and were representative of the adult population of Spain. Data gathered included clinical and demographic characteristics, physical examination, and blood and urine sampling. TSH, free thyroxine, free triiodothyronine, and TPO Ab were analyzed by electrochemiluminescence (E170, Roche Diagnostics, Basel, Switzerland).
  
  
  
  The reference range (p2.5-97.5) for TSH was estimated as 0.6 to 4.8 µUI/mL in the underweight category (BMI<20 kg/m2), 0.6 to 5.5 µUI/mL in the normal-weight category (BMI 20-24.9 kg/m2), 0.6 to 5.5 µUI/mL in the overweight category (BMI 25-29.9 kg/m2), 0.5 to 5.9 µUI/mL in the obesity category (BMI 30-39.9 kg/m2), and 0.7 to 7.5 µUI/mL in the morbid obesity category (BMI ≥40). By using the reference criteria for the normal-weight population, the prevalence of high TSH levels increased threefold in the morbid obesity category (P < 0.01).
  
  
  
  Persons with morbid obesity might be inappropriately classified if the standard ranges of normality of TSH for the normal-weight population are applied to them.
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Valdés
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Maldonado-Araque
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Lago-Sampedro
authors.affiliation: UGC de Laboratorio (Bioquímica), Hospital Regional Universitario de Málaga, Málaga, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Lillo-Muñoz
authors.affiliation: Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.|CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia-Fuentes
authors.affiliation: UGC de Laboratorio (Bioquímica), Hospital Regional Universitario de Málaga, Málaga, Spain.
authors.forename: Vidal
authors.initials: V
authors.lastname: Perez-Valero
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Carolina
authors.initials: C
authors.lastname: Gutiérrez-Repiso
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Garcia-Escobar
authors.affiliation: Department of Endocrinology and Nutrition, Hospital del Mar, Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Goday
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Hospital Universitario Cruces, BioCruces, UPV/EHU, Barakaldo, Spain.
authors.forename: Inés
authors.initials: I
authors.lastname: Urrutia
authors.affiliation: Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Peláez
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Universitario S. Carlos de Madrid, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Calle-Pascual
authors.affiliation: Laboratorio de Bioquímica, Hospital Universitario S. Carlos de Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Bordiú
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Hospital Universitario Cruces, BioCruces, UPV/EHU, Barakaldo, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Castaño
authors.affiliation: Public Health Agency, Department of Health, Autonomous Government of Catalonia, Barcelona, Spain.
authors.forename: Conxa
authors.initials: C
authors.lastname: Castell
authors.affiliation: Department of Endocrinology and Nutrition, Hospital Central de Asturias, Oviedo, Spain.
authors.forename: Elias
authors.initials: E
authors.lastname: Delgado
authors.affiliation: Department of Endocrinology and Nutrition, Hospital Central de Asturias, Oviedo, Spain.
authors.forename: Edelmiro
authors.initials: E
authors.lastname: Menéndez
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|EAP Raval Sud, Institut Català de la Salut, Red GEDAPS, Primary Care, Unitat de Suport a la Recerca (IDIAP - Fundació Jordi Gol), Barcelona, Spain.
authors.forename: Josep
authors.identifier: 0000-0002-5175-1555
authors.initials: J
authors.lastname: Franch-Nadal
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Universitario Cruces - UPV-EHU, Baracaldo, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Gaztambide
authors.affiliation: Diabetes Unit, Hospital Arnau de Vilanova, Valencia, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Girbés
authors.affiliation: CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain.|Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Ortega
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Universitario Joan XXIII, Institut d'Investigacions Sanitaries Pere Virgili, Tarragona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Vendrell
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Universitario Joan XXIII, Institut d'Investigacions Sanitaries Pere Virgili, Tarragona, Spain.
authors.forename: Matilde R
authors.initials: MR
authors.lastname: Chacón
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Genotyping and Genetic Diagnosis Unit, Fundación de Investigación del Hospital Clínico de Valencia-INCLIVA, Valencia, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Javier Chaves
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Soriguer
authors.affiliation: Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.|Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Rojo-Martínez
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000150:complications; D015588:Observer Variation; D050177:Overweight / Q000097:blood / Q000150:complications; D015995:Prevalence; D012016:Reference Values; D013030:Spain; D013851:Thinness / Q000097:blood / Q000150:complications; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D055815:Young Adult
chemical_list: D001323:Autoantibodies; C056626:thyroid microsomal antibodies; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine