title: High Iodine and Salt Intakes and Obesity do not Modify the Thyroid Function in Mexican Schoolchildren.
abstract: Mexico is considered as a nutritional transition country with a high prevalence of overweight and obesity, and recent studies have reported a high iodine intake in children. Both high iodine intake and obesity have been associated with thyroid dysfunction. Our aim was to assess iodine and salt intake and thyroid function in Mexican schoolchildren with normal weight and obesity. A cross-sectional study was performed during 2012-2013 in schoolchildren from Queretaro, Mexico. Six hundred seventy-eight schoolchildren were evaluated to obtain nutrition status, urinary iodine concentration (UIC) and thyroid volume (TVol). The prevalence of overweight and obesity was 47.3 %, the median UIC was 428 μg/L and TVol was normal in all schoolchildren; however, obese girls had a higher TVol than normal weight at the age of 8, 10 and 12 years. A subsample of schoolchildren was divided in 6-8 and 9-12-year-old groups, in order to compare thyroid function (thyrotropin, free T4, and anti-thyroid antibodies); iodine and salt intake were estimated with 24-h urinary samples. No differences in thyroid function were observed in both age groups. In the 6-8-year-old group, obese schoolchildren had higher iodine intake than normal-weight children (415.5 vs. 269.1 μg/day, p < 0.05), but no differences in salt intake. In contrast, in the 9-12-year-old group, obese schoolchildren had higher salt intake than normal-weight children (6.2 vs. 3.8 g/day, p < 0.05), but no differences in iodine intake. Dietary patterns could explain the differences between both age groups. Further studies are needed to identify the main sources of iodine intake in Mexican populations.
authors.affiliation: Laboratorio de Endocrinología y Nutrición, Departamento de Investigación Biomédica, Facultad de Medicina, Universidad Autónoma de Querétaro, Clavel 200. Fracc. Prados de la Capilla, Querétaro, Querétaro, CP. 76176, Mexico.
authors.forename: Lorena
authors.initials: L
authors.lastname: Méndez-Villa
authors.affiliation: Laboratorio de Endocrinología y Nutrición, Departamento de Investigación Biomédica, Facultad de Medicina, Universidad Autónoma de Querétaro, Clavel 200. Fracc. Prados de la Capilla, Querétaro, Querétaro, CP. 76176, Mexico. pablo.garcia@uaq.mx.
authors.forename: Pablo
authors.initials: P
authors.lastname: García-Solís
authors.affiliation: Laboratorio de Endocrinología y Nutrición, Departamento de Investigación Biomédica, Facultad de Medicina, Universidad Autónoma de Querétaro, Clavel 200. Fracc. Prados de la Capilla, Querétaro, Querétaro, CP. 76176, Mexico.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Solís-S
authors.affiliation: Laboratorio de Endocrinología y Nutrición, Departamento de Investigación Biomédica, Facultad de Medicina, Universidad Autónoma de Querétaro, Clavel 200. Fracc. Prados de la Capilla, Querétaro, Querétaro, CP. 76176, Mexico.
authors.forename: David Gustavo
authors.initials: DG
authors.lastname: García-Gutiérrez
authors.affiliation: Laboratorio de Endocrinología y Nutrición, Departamento de Investigación Biomédica, Facultad de Medicina, Universidad Autónoma de Querétaro, Clavel 200. Fracc. Prados de la Capilla, Querétaro, Querétaro, CP. 76176, Mexico.
authors.forename: Valeria Alejandra
authors.initials: VA
authors.lastname: Pérez-Mora
authors.affiliation: Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Querétaro, Mexico.
authors.forename: Ludivina
authors.initials: L
authors.lastname: Robles-Osorio
authors.affiliation: Departamento de Radiología, Vida Care Diagnóstico, Querétaro, Mexico.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Sampson-Zaldívar
mesh_terms: D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage* / Q000652:urine; D008297:Male; D008800:Mexico; D009765:Obesity / Q000378:metabolism* / Q000652:urine; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage* / Q000652:urine; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000378:metabolism*
chemical_list: D017673:Sodium Chloride, Dietary; D007455:Iodine
keywords: Anti-thyroid antibodies; Free thyroxine; Overweight and obese prevalence; Urinary iodine concentration; Urinary sodium concentration