Abstract P104: Association of Thyroid Peroxidase Antibodies and Mortality Risk in Participants of the ELSA-Brasil Cohort Study

Abstract

Introduction: Thyroid peroxidase antibodies (TPOAb) has been considered a new indicator of low-grade inflammation. The presence of TPOAb was associated with a higher risk of cardiovascular diseases and mortality in previous studies. Hypothesis: We assessed the hypothesis that there is an association of TPOAb and risk of mortality in middle-aged participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Methods: Baseline data of 6,115 men and 7,265 women (median age of 50 years-old) were analyzed. Fasting serum TPOAb levels were determined and categorized as detectable (> 5.00 IU/mL) and positive (≥ 34.00 IU/mL). All-cause, cardiovascular, and cancer-related mortality data up to December 2018 were confirmed by death certificate. The association of TPOAb levels, detectability and positivity with mortality was determined by Cox regression, using hazard ratios (HR) and 95% confidence intervals (CI). The final model was adjusted for age, sex, research center, TSH, smoking status, natural log transformed (ln) BMI, alcohol intake, diabetes mellitus, (ln) serum CRP, (ln) serum LDL cholesterol, and hypertension. Results: After a median follow-up of 9 years, the number of events was 296, 86 and 112 for men, and 182, 50, and 85 for women, for all-cause, cardiovascular and cancer-related mortality, respectively. For men, higher levels of TPOAb were significantly associated with cancer-related mortality (HR: 1.25; CI: 1.00-1.57; p=0.049). There was no association of TPOAb levels with all-cause (HR: 1.07; CI: 0.92-1.25) and cardiovascular (HR: 0.73; CI: 0.50-1.08) mortality risk; neither of TPOAb positivity and detectability with any overall or specific mortality risk (p>0.05). For women, the results showed no significant association of TPOAb levels with all-cause (HR: 1.10; CI: 0.97-1.25), cardiovascular (HR: 1.05; CI: 0.81-1.35), and cancer-related (HR: 1.08; CI: 0.89-1.31) mortality. No significant associations were seen between TPOAb detectability and positivity and mortality risk (p>0.05). Conclusions: In conclusion, higher levels of TPOAb were associated with a trend for increased risk of cancer-related mortality among men. Despite this interesting association, a longer period of follow-up is necessary to confirm those results. ELSA-Brasil is a cohort with relatively younger participants and low rates of mortality.