Abstract P661: Potential Determinants Are Associated With Thyroid Peroxidase Antibodies Titers in Men and Women Participants of the ELSA-Brasil Study
Authors: Meneghini Vandrize , Tebar William , Santos Itamar S , Janovsky Carolina , Lotufo Paulo A , Goulart Alessandra C , Bensenor Isabela M 
Published: March 2023

Introduction:
Recently, TPOAb has been highlighted as an indicator of autoimmune diseases in general and low-grade inflammation. However, little is known about the distribution of TPOAb categories according to sociodemographic and lifestyle characteristics.

Hypothesis:
We assessed the hypothesis that potential determinants are associated with multiple categories of TPOAb in euthyroid individuals, according to sex.

Methods:
We analyzed the data of 4,977 males and 5,197 females (median age of 50 years-old), without thyroid diseases, from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) cohort study. Fasting serum TPOAb levels were determined and categorized as undetectable (≤ 5.00 IU/mL), low detectable (5.01-14.99 IU/mL), high detectable (15.00-33.99 IU/mL), and positive (34.00-600.00 IU/mL). Thyrotropin and potential determinants (age, natural log body mass index (lnBMI), self-reported race, education, smoking, and alcohol intake) were also assessed. Adjusted multinomial regression models were applied to determine odds ratio (OR) and 95% confidence intervals (CI), separately for males and females, using the undetectable TPOAb as reference category.

Results:
For males, multivariate analyses showed that higher lnBMI levels were associated with higher odds of having low detectable (OR=2.61, CI=1.13-5.99) and positive (OR=3.11, CI=1.03-9.42) TPOAb. White race and current smokers were associated with low detectable, high detectable, and positive TPOAb (ORs range from 2.05 to 4.58). Participants with higher education were less likely to present TPOAb low and high detectability and positivity, when compared to those with lower education (ORs range from 0.31 to 0.51). Moreover, those with intermediate education and heavy drinkers presented lower odds of TPOAb high detectability (OR=0.58, CI=0.36-0.93) TPOAb positivity (OR=0.52, CI=0.28-0.95), respectively. In the female group, White race and current smokers were associated with higher odds of having low detectable (OR
race
=2.27, CI=1.71-3.02; OR
smoking
=5.33, CI=2.32-12.24), high detectable (OR
race
=2.43, CI=1.78-3.31; OR
smoking
=11.15, CI=4.80-25.92) and positive (OR
race
=2.59, CI=1.85-3.63; OR
smoking
=5.97, CI=2.49-14.33) TPOAb, comparing to non-White race and those that never smoked, respectively. Furthermore, participants with higher and intermediate education, compared to lower education, and heavy drinkers compared to non-drinkers were less likely to present TPOAb detectability and positive (ORs range from 0.23 to 0.47). Age was not significantly associated with TPOAb (p>0.05).

Conclusions:
In conclusion, self-reported race, education attainment, smoking status, and alcohol intake were determinants of TPOAb detectability and positivity for euthyroid men and women. Moreover, higher BMI was associated with low detectable and positive TPOAb only for the male sex.