Endocrine Abstracts

Background: Subclinical thyroid hypofunction and elevation of serum lipid concentrations are two factors that may act synergistically in the increase of cardiovascular risk in patients with type 2 diabetes. However, the association between subclinical hypothyroidism and dyslipidemia is a matter of debate.

Objective: Our aim has been to assess whether incident hypothyroidism detected in a screening program is accompanied by elevations in the serum concentrations of cholesterol and triglyceride in a sample of patients with type 2 diabetes and no previously known dyslipidemia.

Patients and methods: From a total population of 1112 patients with type 2 diabetes who were screened for thyroid dysfunction (thyrotropin measurement) we selected a group of 325 patients with normal thyroid function and another group of 21 patients with incident hypothyroidism (20 of them with subclinical hypothyroidism). No patient had known dyslipidemia nor was taking hypolipidemic medication.

Results: Patients with incident hypothyroidism showed serum concentrations of total cholesterol (4.97±0.73 mmol/l), HDL-cholesterol (1.36±0.33 mmol/l), LDL-colesterol (2.99±0.57) and triglyceride (1.23 (0.89–1.53) mmol/l) that did not differ from those found in euthyroid patients (4.79±0.83, 1.33±0.36, 2.87±0.76 and 1.11 (0.81–1.43) mmol/l, respectively). When analyzing subgroups of women and patients with obesity, we could not find significant differences in lipid profile in patients with hypothyroidism and normal thyroid function. Thyrotropin concentration did not show any correlation with lipid levels in patients with incident hypothyroidism, although we found a significant correlation between thyrotropin and triglyceride in euthyroid subjects (ρ=0.165; P=0.003).

Conclusion: Our results show that, in our population, there are no significant differences in the serum concentrations of cholesterol and triglyceride between diabetic patients with normal and reduced thyroid function.