Incidence of thyroid diseases: Results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

ABSTRACT Objective: To evaluate incidence of subclinical and overt hyperthyroidism and hypothyroidism. Subjects and methods: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) is a prospective cohort study of 15,105 civil servants, examined at baseline and over a 4-year follow-up. This analysis included 9,705 participants with normal thyroid function at baseline, follow-up information about thyroid function and with no report of using drugs that may interfere in the thyroid function. Thyroid function was defined by TSH/FT4 levels or routine use of thyroid hormones/anti-thyroid medications. Annual and cumulative (over 4-year) incidence rates were presented as percentages (95% Confidence Intervals). Results: The incidence of all overt and subclinical thyroid disease was 6.7% (1.73%/year): 0.19% for overt hyperthyroidism (0.048%/year), 0.54% for subclinical hyperthyroidism (0.14%/year), 1.98% for overt hypothyroidism (0.51%/year), and 3.99% for subclinical hypothyroidism (1.03%/year). The incidence of all thyroid diseases was higher in women, when compared to men, with a low women:men ratio (1.36). For Blacks the highest incidence was for overt hyperthyroidism, while for Whites, the highest incidence was for overt hypothyroidism. However, the highest incidence of overt hyperthyroidism was detected in Asian descendants. The presence of antithyroperoxidase antibodies at baseline was associated with higher incidence of overt thyroid diseases. Conclusion: These results showed a high incidence of hypothyroidism, which is compatible with a country with a more-than-adequate iodine intake. The low women:men ratio of the incidence of thyroid dysfunction highlights the importance of the diagnosis of thyroid diseases among men in Brazil.

Thyroid disorders in Brazil: the contribution of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Thyroid disorders are common diseases, both in Brazil and worldwide. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) is a prospective cohort study that investigates cardiovascular diseases, diabetes, and associated factors, including non-classical cardiovascular risk factors such as thyroid function. Thyroid function was classified according to thyrotropin stimulating hormone (TSH), free thyroxine (FT4), and use of medication to treat thyroid disorders, after excluding participants who reported use of any medication that could alter the results of the TSH and FT4 tests. All analyses included in this review are cross-sectional using baseline data (2008 to 2010). The results showed an association of subclinical thyroid disorders with biomarkers of subclinical atherosclerosis, measured by carotid intima-media thickness and coronary artery calcium, insulin resistance, metabolic syndrome, and some psychiatric disorders. No association was found with the biomarker of inflammation high-sensitivity C-reactive protein, or changes in pulse wave velocity or heart rate variability.

Comparison of detection rates of women’s subclinical thyroid diseases between iodine-deficient regions with iodine supplying and water-borne iodine excess regions / 吉林大学学报(医学版)

Objective By comparing the detection rates of subclinical thyroid diseases in women(pregnant,lactating and child-bearing age)between iodine deficient regions (supplied iodized salt)and water-borne iodine excess regions (consumed non-iodized salt),and to find the different prevalence of subclinical thyroid disease between two regions under their different iodine source and iodine levels, and to provide reference for screening susceptible population with iodine-related thyroid diseases.Methods The iodine deficiency but salt iodine surpplying regions were selected from six provinces in our country,the local people who were pregnant women,lactating women and 18 to 45 years old women of child-bearing age,a total of 991 cases were investigated.The iodine nutrition levels of the pregnant women were grouped by 0.05). With the increase of iodine exposure levels,the prevalence of women who suffered from subclinical hypothyroidism and thyroid antibody positive was increased,the coincidence rate was also increased.The detection rates of low T4 concentration and total subclinical thyroid disease of pregnant women in iodine nutrition100μg·L-1 group (P<0.05).Conclusion When the iodine intake is appropriate, iodine intakes from salt or from water have no effect on subclinical thyroid diseases. When the iodine intake increases,the prevalence of subclinical thyroid diseases will increase too.