Estado nutricional de iodo, selênio e função tireoidiana em idosos da Universidade Aberta à Terceira Idade

Abstract

Introduction – Iodine and selenium are essential micronutrients involved in thyroid metabolism. Iodine is used in the synthesis of thyroid hormones T3 and T4, and selenium acts as part of the enzyme iodothyronine 5'-deiodinase type I, thioredoxin reductase and selenoproteins. Objective – This study aimed to evaluate the nutritional status of iodine and selenium, through mean urinary concentration and thyroid function, in elderly people enrolled at the Open University of the Third Age (UATI). Methods – This is an observational, analytical and cross-sectional study, carried out in Salvador (Bahia), in 2019. In this study, urinary iodine and selenium were measured using the ICP-MS analysis method, and thyroid hormones through blood samples measured using the chemiluminescence technique. Results – 118 elderly people participated in the study, with the highest prevalence of women (91.5%), and the median age was 70 years (IQR: 66-73). The nutritional status was adequate according to BMI: 25.2 kg/m² (IQR: 22.3- 29.5), with a prevalence of 53.4% (n=63), but with low values 62.7% (n=74) of calf circumference, characteristic of malnutrition in the elderly. The mean values for iodine (257.5; SD: 150.1), selenium (35.1; SD: 38.1), T3L (2.754; SD: 0.3640) and TSH (2,352; SD: 1,267) were found. Among volunteers with iodine deficiency, selenium levels were lower (median: 10.7; IQR: 5.2-15.3). In those with adequate selenium levels, the values demonstrated excess iodine (median: 400; IQR: 270-549), both being statistically significant (p value < 0.0001). Conclusion – The iodine levels found in the sample demonstrated an excess of the mineral, with values above recommendations, demonstrating a risk for toxicity. Regarding selenium dosage, low levels were found in the studied population. Altered iodine and selenium nutritional status and normal thyroid function were observed. Monitoring iodine and selenium in the elderly is a necessary measure to define the effectiveness of programs to prevent nutritional and health disorders in the population.