Thyroid and the environment: exposure to excessive nutritional iodine increases the prevalence of thyroid disorders in Sao Paulo, Brazil

Autor(es)

Camargo, Rosalinda Y. A. ^[1] ; Tomimori, Eduardo K. ^[2] ; Neves, Solange C. ^[3] ; Rubio, Ileana G. S. ^[4] ; Galrao, Ana Luiza ^[5] ; Knobel, Meyer ^[6] ; Mcdeiros-Neto, Geraldo ^[7]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo. Sch Med

^[2] Univ Sao Paulo. Sch Med

^[3] Univ Sao Paulo. Sch Med

^[4] Univ Sao Paulo. Sch Med

^[5] Univ Sao Paulo. Sch Med

^[6] Univ Sao Paulo. Sch Med

^[7] Univ Sao Paulo. Sch Med

• Tipo de documento: Artigo Científico
• Fonte: EUROPEAN JOURNAL OF ENDOCRINOLOGY; v. 159, n. 3, p. 293-299, SEP 2008.
• Citações Web of Science: 52

Resumo

Objective: To evaluate the prevalence of chronic autoimmune thyroiditis (CAT) and iodine-induced hypothyroidism, hyperthyroidism (overt and subclinical). and goiter in a population exposed to excessive iodine intake for 5 years (table salt iodine concentrations: 40-100 mg/kg salt). Design: This was a population-based, cross-sectional study with 1085 participants randomly selected from a metropolitan area in Sao Paulo, Brazil, and conducted during the first semester of 2004. Methods: Thyroid ultrasound examination was performed in all participants and samples of urine and blood were collected from each subject. Serum levels of thyroid-stimulating hormone, free thyroxine, and anti-thyroid peroxidase (TPO) antibodies, urinary iodine concentration. thyroid volume, and thyroid echogenicity were evaluated. We also analyzed table salt iodine concentrations. Results: At the time the study was conducted, table salt iodine concentrations were within the new official limits (20-60 mg/kg salt). Nevertheless, in 45.6%, of the participants, urinary iodine excretion was excessive (above 300 mu g/l) and, in 14.1%, it was higher than 400 mu g/l. The prevalence of CAT (including atrophic thyroiditis) was 16.9% (183/1085), women were more affected than men (21.5 vs 9.1% respectively, P=0.02). Hypothyroidism was detected in 8.0%, (87/1085) of the Population with CAT. Hyperthyroidism was diagnosed in 3.3% of the individuals (36/1085) and goiter was identified in 3.1% (34/1085). Conclusions: Five years of excessive iodine intake by the Brazilian population may have increased the prevalence of CAT and hypothyroidism in subjects genetically predisposed to thyroid autoimmune diseases. Appropriate screening for early detection of thyroid dysfunction may be considered during excessive nutritional iodine intake. (AU)

• Processo FAPESP: 03/00827-0 - Estudo comparativo de prevalência de tireoidite de Hashimoto na população vicinal ao Pólo Petroquímico de Capuava e área controle na região metropolitana da Grande São Paulo
• Beneficiário: Geraldo Antônio de Medeiros Neto
• Modalidade de apoio: Auxílio à Pesquisa - Regular