Serum thyroid hormone balance and lipid profile in patients with epilepsy

Patients with epilepsy may exhibit changes in thyroid hormone balance, lipids and lipoproteins concentrations. The suggestion that lipid abnormalities are associated with subclinical thyroid dysfunction remains controversial. The aim of this study was to analyze whether thyroid dysfunction encountered in patients with epilepsy would also be associated with abnormal lipid profile.

Eighty-eight patients with epilepsy and 30 control subjects were included in the study. A fasting blood sample for thyroid hormones, lipid profile and GGT determination was obtained.

The serum levels of FT3 was elevated in 10.2% of patients, FT4 was low in 28.4%, TSH was high in 4.6% and low in 2.3%. 13.6% of patients had high TC, 17.1% had high LDL-c, 60.2% had marked reduction of HDL-c levels (P<0.0001) and only 2.3% had high TG levels. Abnormalities were predominated in CBZ-treated patients. 27.3% patients with abnormal hormones had abnormal lipid profile. Significant association was identified between the serum TC, LDL-c, TG, GGT and EIAEDs and between the duration of illness and TG (r=-0.411; P=0.017), and FT4 (r=-0.412; P=0.018). HDL was higher in women than men (r=0.416; P<0.002). However, changes in HDL-c levels associated neither with duration of illness, type or serum levels of AEDs nor with age or degree of control on AEDs.

Our results support that (1) altered lipid metabolism might be associated but not solely influenced by thyroid hormones and (2) enzyme induction is not the main or only reason for altered thyroid function or HDL-c among patients with epilepsy. Hypothalamic/pituitary dysregulation by precisely mechanism caused by epilepsy itself or AEDs seems possible and (3) it is important to recognize that patients with epilepsy are at great risk for atherosclerosis, hence monitoring and correction of the culprit risks are mandatory.