Thyroid Function and Its Relationship to Lipid Metabolism and Cardiovascular Risk in Adults with Subclinical Hypothyroidism in Akure, South West Nigeria

Background: Subclinical hypothyroidism, defined by elevated thyroid-stimulating hormone with normal free thyroxine, is associated with dyslipidaemia and increased cardiovascular risk through alterations in lipoprotein metabolism and myocardial function. The prevalence and cardiovascular physiological consequences of subclinical hypothyroidism in Ondo State, South West Nigeria have not been systematically studied. Objectives: This study aims to determine the prevalence of subclinical hypothyroidism, compare lipid profiles and non-invasive cardiovascular parameters including echocardiographic left ventricular function and brachial-ankle pulse wave velocity between adults with and without subclinical hypothyroidism attending a tertiary facility in Akure. Methods: One thousand adults aged 30 to 65 years will be screened for thyroid function. Those with confirmed subclinical hypothyroidism will be matched with euthyroid controls by age, sex, and body mass index. Fasting lipid profiles, echocardiography, and pulse wave velocity will be assessed. Multivariate logistic regression will identify subclinical hypothyroidism as a predictor of lipid and cardiovascular abnormalities. Expected Outcomes: Subclinical hypothyroidism is anticipated to be associated with elevated low-density lipoprotein cholesterol, impaired diastolic function, and higher pulse wave velocity, independent of traditional cardiovascular risk factors. Conclusion: Findings will provide evidence for routine thyroid screening as part of cardiovascular risk assessment in Nigerian adults. Keywords: subclinical hypothyroidism, dyslipidaemia, cardiovascular risk, thyroid function, Akure.