Increased mean serum thyrotropin in apparently euthyroid hypercholesterolemic patients: does it mean occult...

Area of Science:

• Endocrinology
• Metabolic Disorders
• Clinical Chemistry

Background:

• Hypercholesterolemia is a significant risk factor for cardiovascular disease.
• Thyroid dysfunction, particularly hypothyroidism, can contribute to dyslipidemia.
• The relationship between subclinical thyroid dysfunction and hypercholesterolemia requires further investigation.

Purpose of the Study:

• To investigate the prevalence of thyroid autoimmunity and dysfunction in hypercholesterolemic individuals.
• To compare thyroid hormone levels and antithyroid autoantibodies (AAB) between hypercholesterolemic patients and normocholesterolemic controls.
• To explore the correlation between serum total cholesterol (TC) and thyroid-stimulating hormone (TSH) levels.

Main Methods:

• Assay of serum thyroid hormones and antithyroid autoantibodies (AAB) in 87 hypercholesterolemic individuals and 80 controls.
• Measurement of serum total cholesterol (TC) and thyroid-stimulating hormone (TSH).
• Statistical analysis to compare groups and identify correlations.

Main Results:

• A higher prevalence of positive AAB was observed in hypercholesterolemic persons (25%) compared to controls (6%).
• Eight hypercholesterolemic patients (9%) had undiagnosed subclinical hypothyroidism (TSH > 5 mU/l).
• Hypercholesterolemic individuals exhibited significantly higher average TSH levels than controls, even after excluding those with positive AAB. A positive correlation between TC and TSH was found.

Conclusions:

• Hypothyroidism may present as a spectrum rather than an absolute condition.
• Subtle thyroid function impairment, indicated by elevated TSH within the conventional normal range, may be common in hypercholesterolemia.
• These findings suggest a potential link between subclinical hypothyroidism and hypercholesterolemia, warranting further clinical consideration.