Relationship between TSH Levels and the Advanced Lipoprotein Profile in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Abstract

Purpose/aims: The relationship between thyroid-stimulating hormone (TSH) and lipoprotein subfractions by Vertical Auto Profile (VAP) is unclear. We aimed to evaluate lipoprotein profiles according to TSH levels in euthyroid individuals.Material and Methods: Cross-sectional analysis of 3,525 participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) with no previous thyroid disease and who were not on lipid-lowering medication. Total-cholesterol and its fractions, lipoprotein subfractions, triglycerides, and triglyceride-rich lipoprotein cholesterol [TRL-C (VLDL₁₊₂-C, VLDL₃-C, IDL-C)] were determined by VAP. Associations between TSH quintiles and lipoprotein subfractions were evaluated by crude and adjusted linear regression models.Results: For the total sample, significant beta-coefficients in full adjusted models for the 5^th quintile of TSH (compared to 1^st) were found for the following VAP lipids and lipoproteins: IDL-C (β: 0.90; 0.11 to 1.69); VLDL-C (β: 2.80; 1.51 to 4.08), triglycerides (β: 18.66; 8.07 to 29.25), non-HDL-C (β: 4.63; 0.50 to 8.75 mg/dl), TRL-C (β:1.93;0.70 to 3.17), VLDL₃-C (β: 1.04; 0.50 to 1.57), as well as, TC/HDL-C (β: 0.15; 0.03 to 0.26) and TG/HDL-C ratio (β: 0.49;0.21 to 0.77). In women, similar results were found for VLDL-C, triglycerides, non-HDL-C, TRL-C, VLDL₃-C, TC/HDL-C and TG/HDL-C-ratios. In men, we also found positive associations between the highest quintile of TSH with VLDL-C, triglycerides, VLDL₃-C and TG/HDL-C.Conclusions: In the ELSA-Brasil, the highest TSH levels were mostly positively associated with lipoprotein levels, particularly TG, TRL and their remnants. Notwithstanding, our findings suggest that TSH levels within the normal range have little impact on the atherogenic profile.