Lillo-Munoz J.A.,Ugc Of Laboratorio Bioquimica Hospital Regional Universitario Of Malagamalaga Spain |
Garcia-Fuentes E.,CIBER ISCIII |
Perez-Valero V.,Ugc Of Laboratorio Bioquimica Hospital Regional Universitario Of Malagamalaga Spain |
Urrutia I.,Hospital Universitario Cruces |
And 9 more authors.
Obesity | Year: 2017
Objective: To analyze the reference range of thyroid-stimulating hormone (TSH) in different BMI categories and its impact on the classification of hypothyroidism. Methods: 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). Results: 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). Conclusions: 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. © 2017 The Obesity Society.