Predictors of atherosclerosis and dyslipidaemia among patients with thyroid disease: a cross-sectional analysis

Background: Thyroid dysfunction is a risk factor for cardiovascular disease through its effects on lipid metabolism and arterial wall remodelling. However, the relative contributions of thyroid autoimmunity versus hormone deficiency to dyslipidaemia and atherosclerotic disease remain incompletely characterised in ageing populations.

Objectives: To investigate the independent associations between thyroid dysfunction (overt hypothyroidism, subclinical hypothyroidism, overt hyperthyroidism, and subclinical hyperthyroidism) and early atherosclerotic markers, including lipid profiles, carotid intima-media thickness (CIMT), and to identify key predictors of hypercholesterolemia in an adult Indian population with thyroid dysfunctions.

Methods: This cross-sectional observational study enrolled 82 consecutive adult patients with thyroid dysfunction from a tertiary care centre in eastern India. Patients receiving active thyroid hormone supplementation, antithyroid medication, or lipid-lowering treatment, including current statin therapy, were excluded. Thyroid and lipid measurements were performed using routine automated clinical laboratory methods, and participants underwent carotid ultrasound assessment. Multivariable binary logistic regression was performed to identify exploratory predictors of elevated total cholesterol (>200 mg/dL), with odds ratios, 95% confidence intervals and the area under the receiver operating characteristic curve (AUC) used to describe internal model performance. Consecutive eligible patients were recruited over a prespecified 12-month feasibility period; the sample size was based on available recruitment and supported by a post-hoc power/precision assessment for the principal correlation analyses.

Results: Overt hypothyroidism was associated with higher CIMT and a greater burden of abnormal CIMT categories than the other thyroid-status groups. Total cholesterol was highest in the overt hypothyroid group, and TSH was positively correlated with CIMT in the overall cohort (Spearman rho = 0.65; p < 0.001). Peak systolic velocity was also highest in overt hypothyroidism. In exploratory multivariable logistic regression, log10(Anti-TPO) was associated with hypercholesterolaemia (OR 13.629, 95% CI: 1.174-190.489; p = 0.0421), whereas log10(TSH) was not independently associated after adjustment (OR 1.243, p = 0.6904). The wide confidence interval indicates substantial imprecision and the finding requires external validation. The internally assessed logistic model showed acceptable discrimination (AUC 0.834, 95% CI: 0.748-0.920), and Anti-TPO was positively correlated with CIMT (rho = 0.60; p < 0.001).

Conclusion: Overt hypothyroidism was associated with early atherosclerotic changes and dyslipidaemia in this exploratory single-centre cohort. Anti-TPO antibodies correlated with CIMT and were associated with elevated total cholesterol in an adjusted model, but the imprecision of the estimate and cross-sectional design mean that these findings should be considered hypothesis-generating and require prospective external validation before clinical implementation.