Endocrine Abstracts

Serum levels of TSH in euthyroid individuals are frequently associated with favorable outcomes. However, whether this association is merely an epiphenomenon of longevity or whether TSH may correlate with a metabolic protective profile is unclear. We investigated the putative association between TSH serum levels and cardiovascular outcomes in euthyroid participants. We hypothesized that participants with higher TSH might present a protective cardiovascular clinical profile. We critically analyzed the baseline data from the cohort study ELSA-Brasil. Thyroid function was evaluated in 11,179 participants aged between 35 and 74 years, who were classified as euthyroid and followed by 7,7±0.6 years. Biochemical analytes, including serum glucose, triglycerides, total cholesterol, LDL, HDL, Lp(a), and ApoB, were evaluated. Clinical data were assessed, looking for relevant outcomes such as coronary disease, heart failure, and all-cause mortality. A statistical analysis compared TSH as predictive of biochemical and clinically relevant outcomes. TSH was linearly correlated with age (Spearman rank= +0.024; P = 0.012). Individuals with hypertriglyceridemia have higher levels of TSH (1.97±0.835 mIU/l) than individuals without hypertriglyceridemia (1.86±0.814 mIU/l, P < 0.05). Individuals without diabetes have higher serum TSH levels (1.89±0.818 mIU/l) than individuals with diabetes (1.80±0.831 mIU/l P < 0.05). Patients with established coronary disease and heart failure had lower TSH levels (1.76±0.813 mIU/l and 1.67±0.846 mIU/l) than those individuals who did not have these conditions (1.88±0.820 mIU/l and 1.88±0.820 mIU/l, P < 0.05 respectively). We failed to demonstrate a correlation between TSH and cholesterol, LDL, HDL, Lp(a), and ApoB. We categorized individuals into higher and lower TSH groups based on the median. Individuals with TSH higher than the median presented a longer survival time than those with TSH lower than the median, suggesting that TSH might be correlated with a better survival rate. Our data reinforce that euthyroid individuals with higher TSH levels have a biochemical profile associated with cardiovascular risk, such as hypertriglyceridemia. However, the increase in An increased risk of cardiovascular events does not accompany TSH. In contrast, individuals with higher TSH presented with the absence of diabetes, coronary disease, heart failure, and better survival. More studies are warranted to investigate the mechanisms behind the association of TSH with cardiovascular protection and longevity.