FAT DISTRIBUTION AND METABOLIC PROFILE IN SUBJECTS WITH HASHIMOTO'S THYROIDITIS

Previous studies have associated overt/subclinical hypothyroidism and obesity but have failed to confirm a causative relationship between them. Confusion is even more for subjects with Hashimoto's Thyroiditis (HT).

In this study, we aimed to evaluate the fat distribution and metabolic profile of subjects with euthyroid HT as well as to establish an appropriate cut-off level of TSH for the development of metabolic syndrome (Mets) in both groups.

All subjects were euthyroid whether under levothyroxine replacement or not. We recruited 301 volunteers (99 with HT and 202 without thyroid autoimmunity). Together with some metabolic variables, we measured the waist circumference, hip circumference, neck circumference manually; the total body fat with a body composition analyzer; and the visceral fat/trunk fat percentage via abdominal bioelectrical impedance analysis.

A significant positive correlation was established between TSH levels and insulin, fasting plasma glucose, HOMA-IR and body mass index (r=0.28; p<0.001; r=0.27; p<0.05: r=0.32; p<0.001: r=0.13; p<0.05 respectively). The prevalence of Metabolic Syndrome (Mets) was comparable in HT and control groups (27.3% vs. 30.7%; p>0.05). The prevalence of Mets was similar when HT subjects using levothyroxine or HT subjects with accompanying thyroid nodules were taken into consideration. Similarly, anthropometric and metabolic parameters were similar in both the HT group and the control group.We were unable to establish the TSH cut-off level by ROC analysis with desired sensitivity and specificity (AUC: 0.563 with 95% C.I. p=0.35; standard error 0.76).

Although weight gain is frequently encountered in subjects with HT, such subjects with thyroid function tests in the euthyroid range have a similar prevalence of Mets and similar metabolic and anthropometric measurements compared to subjects without autoimmunity.