Molecular
The metabolic vulnerability index in subclinical hypothyroidism: a cross-sectional analysis from ELSA-Brasil Vandrize Meneghini* Vandrize Meneghini Carolina Castro Porto Silva Janovsky William R. Tebar José Augusto Sgarbi Patrícia de Fatima dos Santos Teixeira Steven R. Jones Michael J. Blaha Peter P. Toth Paulo A. Lotufo Isabela M. Benseñor
Introduction: The metabolic vulnerability index (MVX) is a novel biomarker of cardiovascular mortality risk derived from inflammation (IVX) and malnutrition (MMX) markers. Elevated MVX scores correlate with increased cardiovascular mortality. These indices have not been studied in thyroid disorders.
Objective: To explore the association of subclinical hypothyroidism with IVX, MMX, and MVX scores.
Methods: This is a cross-sectional analysis using baseline data from the São Paulo Research Center of the ELSA-Brasil study. Individuals with normal thyroid function (n=3722, mean age 51±9) and subclinical hypothyroidism (n=395, mean age 52±9) were included. Thyroid function was classified according to thyrotropin and free thyroxine levels and thyroid replacement therapy. Individuals taking medication that interferes with thyroid function were excluded. The components of IVX (GlycA, small high-density lipoprotein particles) and MMX (valine, leucine, isoleucine and citrate) were measured by nuclear magnetic resonance spectroscopy (LipoProfile® 4 test spectra, LabCorp). Sex-specific MMX and IVX scores were calculated and combined as MVX scores. We performed generalized linear regression analysis and included sociodemographic and lifestyle factors, chronic diseases, cardiovascular history, and glomerular filtration rate as confounder variables.
Results: Subclinical hypothyroidism was associated with higher MMX (ꞵ=1.16, 95% CI=1.05-1.28) and MVX (ꞵ=1.13, 95% CI=1.02-1.25) scores. After full adjustment, subclinical hypothyroidism was positively associated with MVX scores (ꞵ=1.12, 95% CI=1.02-1.23) compared with normal thyroid function. Participants with subclinical hypothyroidism showed positive, but not significant, association with MMX (ꞵ=1.09, 95% CI=0.99-1.20) and IVX (ꞵ=1.09, 95% CI=0.99-1.20) scores.
Conclusion: The association of subclinical hypothyroidism with these novel indices indicates that this disorder is a potential risk factor for cardiovascular mortality.