Lipid Profile Pitfalls in Subclinical Hypothyroidism Pathophysiology and Treatment

Background: Lipids encompass a diverse group of biomolecules that are crucial for maintaining the body’s internal equilibrium and for a range of functions, including energy storage, maintenance of cellular membranes, and cellular signalling. Their synthesis and metabolism are intricately linked to hormonal regulation, particularly by thyroid hormones, which influence lipid metabolism by modulating gene expression, enzyme activity, and mitochondrial function. Thyroid hormones enhance the metabolic rate, lipid clearance, and cholesterol conversion to bile acids, which are regulated through feedback mechanisms involving the hypothalamic–pituitary–thyroid axis. Subclinical hypothyroidism (SCH) presents a complex challenge in understanding lipid metabolism. Methods: Research on SCH’s impact on lipid profiles has yielded conflicting results. Some studies indicate that SCH is associated with increased levels of cholesterol and triglycerides, while others report no significant changes. These discrepancies underline the necessity for more comprehensive studies to clarify how SCH affects lipid metabolism and its potential cardiovascular implications. Conclusions: This review aims to consolidate the existing knowledge, exploring the biochemical pathways and clinical evidence that link thyroid dysfunction with lipid abnormalities and cardiovascular health risks. It emphasizes the critical need for further research to elucidate the full impact of SCH on lipid metabolism and its broader effects on cardiovascular health, guiding future interventions and treatment strategies.