Objective: Morbid obesity (body mass index (BMI)R40 kg/m 2 ) is associated with thyroid function disturbances, with a high rate of subclinical hypothyroidism (SH) being the most consistently reported. We evaluated the circulating thyroid function parameters in morbid obese patients and related the results to the presence of circulating thyroid antibodies (Thyr-Ab). Design and methods: Morbid obese patients were consecutively enrolled (nZ350). Two control groups were used: control group (CG)1, healthy normo-weight subjects (nZ50); CG2, normo-weight patients with SH (nZ56) matched for TSH with the obese patients with SH. Serum levels of free triiodothyronine (FT 3 ), free thyroxine (FT 4 ), TSH, antithyroglobulin antibodies, and antithyroperoxidase antibodies were measured in all patients. Results: i) Compared with CG1, obese patients having thyroid function parameters in the normal range and negative Thyr-Ab showed significantly higher serum TSH and lower free thyroid hormones levels, but a similar FT 4 /FT 3 ratio; ii) SH was recorded in 13.7% obese patients; iii) compared with CG2, obese patients with untreated SH had a significantly lower rate of positive Thyr-Ab (32.1 vs 66.1%; P!0.005); iv) no gender prevalence was observed in SH obese patients with negative Thyr-Ab; and v) the comparison of the untreated SH patients (obese and normo-weight) with CG1 demonstrated that in SH obese subjects, unlike normo-weight SH patients, the FT 3 levels were significantly lower. This resulted in a normal FT 4 /FT 3 ratio in SH obese patients. Conclusion: Thyroid autoimmunity is not a major cause sustaining the high rate of SH in morbid obese patients. In these patients, the diagnosis of SH itself, as assessed by a raised TSH alone, appears questionable.

APA measurement by immunofluorescence may help to predict the occurrence of hypopituitarism but only when considering the immunostaining pattern and their titers. Combined evaluation of these parameters allows identifying patients at higher risk for pituitary autoimmune dysfunction, thus requiring a strict pituitary surveillance to disclose a preclinical phase of hypopituitarism and possibly interrupt therapeutically the progression to clinically overt disease.

ILP represents a valid alternative to surgery also for large benign thyroid nodules, both in terms of nodule size reduction and cure of hyperthyroidism (87% of cured patients after the last ILP cycle). ILP should not be limited to patients refusing or being ineligible for surgery and/or radioiodine.

The PP period is significantly associated with a relapse of hyperthyroidism in GD patients being in remission after ATD. We therefore recommend that patients with GD in remission after a course of ATD should have their thyroid function tested at 3 and 6 months after delivery.