Subclinical hypothyroidism and the risk of hypercholesterolemia.

INTRODUCTION: Subclinical hypothyroidism (SCH) is a condition wherein there are small elevations in thyroid stimulating hormone (TSH), yet normal circulating levels of free thyroid hormones (FT4). Alterations in thyroid function result in changes in composition and transport of lipoproteins.

METHODS: The study was undertaken in the outpatient department of Lourdes hospital, Ernakulam. 110 patients between 40-69 years were studied, of which 60 were identified to have SCH based on cross-sectional survey, 50 patients were randomly selected to represent the EU group. Data based on interview, clinical examination, thyroid function, lipid profiles. Student's t, chi-square tests used for computation of p values.

RESULTS: SCH were seen in females (66.66%) and in the age group of 40-49 years (61.66%). Mean cholesterol values were elevated in the subclinical hypothyroid group and in relation to age (60-69) and gender. Statistical analysis showed significant difference in total cholesterol(TC) (P<0.005) and triglycerides (P<0.05) in relation to age (40-49 yrs.) between two groups. Based on TSH, group A 5-7.49Mu/L and group B 7.5-10Mu/L were compared to the euthyroid group N<5Mu/L. Mean cholesterol values were raised in both subgroups. Statistically significant difference seen (P<0.0005) in cholesterol values between the subclinical hypothyroid group B and the euthyroid group N.

CONCLUSIONS: SCH appears to be associated with increased mean cholesterol levels in females and of age > 60 years. The TC values were elevated in both subgroups of patients with SCH (A and B) based on TSH values.