Introduction: The repercussion of subclinical hypothyroidism and its treatment on the levels of circulating lipids has received scarce definition. With the aim of obtaining our own data for evaluating the need of treatment in this pathology, we designed a study protocol in two phases.
Material and methods: In the first phase we determined the plasma values of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides, Apo A-I, Apo B-100 and Lp(a) in two groups of patients: a control group formed by 123 healthy women from a Pamplona Health Area and a second group formed by 29 women affected by subclinical hypothyroidism who were attending our surgeries. In the second phase we included 42 women with subclinical hypothyroidism, on whom we carried out a comparative longitudinal study for three months, dividing them into two groups. One that was formed by 30 women, who were treated until their levels of TSH were normalised, and another in which the women were left in subclinical hypothyroidism. In both groups we have evaluated the lipidic profile and Apo A-I, Apo B100 and Lp (a).
Results: 1st phase: The total cholesterol and the LD-cholesterol were significantly higher in the group with SH than in the control group. There were no differences in the HDL-cholesterol nor in the triglycerides. 2nd phase: Group 1: The figures of total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and Lp (a) were not modified on normalisation of the levels of TSH. The Apo A-I increased significantly and the Apo B-100 showed a tendency to diminish although without significant differences. Group 2: None of the parameters changed significantly as they remained in subclinical hypothyroidism. On comparing the final parameters between groups 1 and 2 (after 3 months), only the Apo A-I and the Lp (a) increased significantly on correction of SH.
Conclusions: Subclinical hypothyroidism is accompanied by a modification of the lipidic profile of an atherogenic character although its treatment, according to our data, does not achieve significant variations.