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

OBJECTIVE: To evaluate incidence of subclinical and overt hyperthyroidism and hypothyroidism. 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.

The association of waist-to-height ratio and other anthropometric measurements with subclinical atherosclerosis: Results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

BACKGROUND AND AIMS: To compare the performance of waist-to-height ratio (WHtR), waist-to-hip ratio (WHR), waist circumference (WC) and Body-mass index (BMI) with subclinical atherosclerosis. METHODS AND RESULTS: The association of quintiles of anthropometric variables (1st as reference) - Odds ratio (OR); 95% Confidence Interval (95% CI) - with Coronary Artery Calcium (CAC: 0 vs. >0; <100 vs. ≥100), Carotid Intima-Media Thickness (CIMT: <75th vs. ≥P75%) and as continuous variables in linear regression models in 4216 participants of ELSA-Brasil baseline. WHtR was associated with CAC >0 (OR, 1.84; 95% CI, 1.16-2.93) and ≥100 after multivariate adjustment including BMI. WHR was associated with CAC >0 OR, 1.81 (95% CI, 1.25-2.82) and ≥100. BMI was not associated with CAC after further adjustment for WHtR, but was associated with CAC >0 after adjustment for WHR (OR, 1.42; 95% CI, 1.02-1.94) or WC (1.63; 95% CI, 1.03-2.59). WHtR was not associated with CIMT after further adjustment for BMI. WHR was associated with CIMT ≥P75% (OR, 1.44; 95% CI, 1.02-2.02) and in linear models (p < 0.0001). WC was associated with CIMT in linear models (p < 0.0001). BMI was associated to CIMT ≥P75% (OR, 2.25; 95% CI, 1.53-2.54); and in linear models (P < 0.0001) after further adjustment for WHtR. After adjustment for WHR and WC the association of BMI with CIMT ≥P75% was respectively (OR 2.31; 95% CI, 1.70-3.13; and OR 2.39; 95% CI, 1.55-3.70); and in both linear models (p < 0.0001). CONCLUSIONS: WHtR was a good biomarker for subclinical atherosclerosis measured by CAC while BMI was a good biomarker for CIMT. WHR presented the best performance being associated with both biomarkers of subclinical atherosclerosis.