Unfavorable triglyceride-rich particle profile in subclinical thyroid disease: A cross-sectional analysis of ELSA-Brasil

Introduction: Subclinical thyroid disorders have been associated with
atherosclerosis and increased cardiovascular risk. As triglyceride-rich
lipoprotein particles (TRLP) have recently emerged as a casual factor for
atherogenesis, the aim of this study was to evaluate the relationship
between subclinical hypo and hyperthyroidism and TRLP subfractions.
Methods: We selected 5,066 participants from the ELSA-Brasil cohort with
available data of thyroid function and lipid profile measured by NMR.
Individuals were divided into three groups by baseline thyroid function
(subclinical hypothyroidism, euthyroidism, and subclinical
hyperthyroidism). TRLP subfractions were analyzed through Nuclear Magnetic
Resonance (NMR) spectroscopy. To examine the association between TRLP
subfractions and thyroid function, we conducted univariate and
multivariate linear regression models adjusted for demographic
characteristics, BMI, diabetes, smoking status and alcohol use. Results:
Of 3,304 individuals, 54% were women, with a mean age of 50.6±8,7 years,
51% white and 53% with at least college education. Of these individuals,
92% were euthyroid, whereas 6.8% had subclinical hypothyroidism and 1.2%
had subclinical hyperthyroidism. The univariate linear regression showed
that Very Small TRLP (p=0.026) and Very Large TRLP (p=0.008) were
statistically increased in subclinical hypothyroidism when compared to
euthyroidism. In subclinical hyperthyroidism, there was a reduction in
total TRLP (p=0.003), seemingly driven by reduced Very Small-TRLP
(p=0.067). The findings were confirmed when adjusted for demographic
characteristics, as well as comorbidities. Conclusions: This study
suggests that subclinical hypothyroidism is associated to very small and
very large TRLP, which are related to an unfavorable atherogenic profile.
Subclinical hyperthyroidism is associated to lower very small TRLP.