Incidence of TPOAb over a 4-year follow-up period: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Author(s)

Isabela M. Benseñor ^[1] ; Carolina Castro Porto Silva Janovsky ^[2] ; Alessandra C. Goulart ^[3] ; Itamar de Souza Santos ^[4] ; Maria de Fátima Haueisen Sander Diniz ^[5] ; Bianca de Almeida-Pititto ^[6] ; José Augusto Sgarbi ^[7] ; Paulo A. Lotufo ^[8]

Affiliation

^[1] Universidade de São Paulo. Divisão de Clínica Médica. Hospital Universitário - Brasil

^[2] Universidade de São Paulo. Divisão de Clínica Médica. Hospital Universitário - Brasil

^[3] Universidade de São Paulo. Divisão de Clínica Médica. Hospital Universitário - Brasil

^[4] Universidade de São Paulo. Divisão de Clínica Médica. Hospital Universitário - Brasil

^[5] Universidade Federal de Minas Gerais. Faculdade de Medicina - Brasil

^[6] Universidade de São Paulo. Faculdade de Saúde Pública. Departamento de Epidemiologia - Brasil

^[7] Faculdade de Medicina de Marília. Departamento de Medicina. Divisão de Endocrinologia e Metabolismo - Brasil

^[8] Universidade de São Paulo. Divisão de Clínica Médica. Hospital Universitário - Brasil

• Document type: Journal article
• Source: ARCHIVES OF ENDOCRINOLOGY METABOLISM; v. 65, n. 6, p. 832-840, 2021-11-22.

Abstract

ABSTRACT Objective: Although some previous data have suggested a high iodine intake in Brazil, the prevalence of antithyroperoxidase antibodies (TPOAb) in the country is compatible with rates from countries with adequate iodine intake. This observation emphasizes the importance of knowing the incidence of TPOAb in Brazil. Materials and methods: This prospective analysis included euthyroid participants with negative TPOAb at baseline and a thyroid function assessment at a 4-year follow-up. TPOAb was measured by electrochemiluminescence and considered positive when titers were ≥34 IU/mL. TSH and free T4 (FT4) levels were determined by a third-generation immunoenzymatic assay. The incidence of TPOAb is expressed in percentage per year or as a cumulative incidence within the 4-year follow-up period. Results: Of 8,922 euthyroid participants (mean age 51.1 years; 50.9% women) with a negative TPOAb test at baseline, 130 presented incident TPOAb at the 4-year follow-up, yielding an annual incidence of TPOAb of 0.38%/year (95% confidence interval [95% CI], 0.37-0.39%/year) and a cumulative incidence over 4 years of 1.46% (95% CI, 1.21-1.71%). In men, the annual incidence was 0.32% (95% CI, 0.31-0.33%), and the cumulative incidence over 4 years was 1.23% (95% CI, 0.90-1.56%). In women, the annual incidence was 0.43%/year (95% CI, 0.42-0.44%/year) and the cumulative incidence over 4 years was 1.67% (95% CI, 1.30-2.04%). The only factor associated with incident TPOAb was the occurrence of thyroid diseases at follow-up. No differences in TPOAb incidence were detected across ELSA-Brasil research centers. Conclusion: Based on the results of this study, the incidence of TPOAb per year and at a 4-year follow-up period are compatible with those of a country with adequate iodine intake. (AU)

• FAPESP's process: 15/17213-2 - Incidence of thyroid subclinical and overt thyroid disorders in the Brazilian Longitudinal Study of Adult Health
• Grantee: Isabela Judith Martins Bensenor
• Support Opportunities: Research Projects - Thematic Grants