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Introducción: El rendimiento del estudio de función tiroidea en niños obesos es desconocido. Nuestro objetivo fue describir en esta población los niveles de hormona tiro-estimulante (TSH) y tiroxina plasmática libre (T4L), los factores asociados y la frecuencia de hipotiroidismo. Pacientes y Método: Estudio retrospectivo de 260 fichas clínicas de niños obesos que consultaron a una nutrióloga infantil por primera vez entre enero de 2007 y junio de 2012. Se consignó la edad, sexo, pubertad, peso, talla y perímetro de cintura (PC). Calculamos el índice de masa corporal (IMC, z-score), peso/talla (IPT) y talla/edad (NCHS 2000). Se determinaron los niveles de TSH y T4L. Resultados: Se incluyeron 210 pacientes entre 2 y 18 años, 59% mujeres, 51,4% pre-púberes. 23,9% sobrepeso y 76,1% obesidad. 70,8% presentó obesidad central. TSH y T4L fueron 2,31 μUI/mL (0,69 a 8,07) y 1,289 ± 0,17 ng/dL, respectivamente. Se encontró hipotiroidismo en 21 pacientes (10%), subclínico en 20 de éstos. Hubo una correlación inversa de LogTSH con edad y directa de LogTSH con zIMC. Con regresión múltiple solamente zIMC fue significativo (p < 0,001, R2 ajustado 8,2%, β 0,19). No hubo diferencias en edad, sexo, pubertad ni estado nutricional entre eutiroideos e hipotiroideos. Conclusión: Encontramos 9,5% de hipotiroidismo subclínico, lo cual justifica el tamizaje con TSH en niños obesos. Introduction: Study results regarding thyroid function in obese children are unknown. The objective of this study was to describe the levels of thyroid stimulating hormone (TSH), free plasma thyroxine (FT4), associated factors and frequency of hypothyroidism in these children. Patients and Method: A retrospective study of medical records of 260 obese children who consulted a physician for the first time between January 2007 and June 2012. Age, gender, puberty, weight, height and waist circumference (WC) were considered; body mass index (BMI z -score), weight/height (IPT) and height/age (NCHS 2000) were calculated, and TSH and FT4 were measured. Results: 210 patients aged 2 to 18 years were included, 59% female, 51.4% prepubescent children, 23.9% were overweight and 76.1% obese. 70.8% of the children surveyed had central obesity. TSH and FT4 values were 2.31 μUI/mL (0.69 to 8.07) and 1.289 ± 0.17 ng/dL, respectively. Hypothyroidism was found in 21 patients (10%), 20 of these presented it as subclinical condition. An inverse correlation was present between age and log TSH and a direct correlation was described between log TSH and zBMI. Qnly zBMI was significant (p < 0.001, adjusted R2 8.2%, β 0.19) after using multiple regression. No differences in age, gender, nutritional status and puberty between euthyroid and hypothyroid patients were found. Conclusion: 9.5% of patients presented subclinical hypothyroidism, which supports TSH screening in obese children. |
