The Effect of Bariatric Surgery on Thyroid Function and Morphology

Background:

Over the last decades, there has been an increase in obesity in virtually all population groups with approximately 1.6 billion adults worldwide estimated to be overweight in 2005 and 400 million of these people qualifying as being obese.

Although hormonal disturbances may play a certain role in the development of obesity, more important are the possible consequences of obesity and the influence of surgically-induced rapid weight loss on overall endocrine function of these patients. Studies evaluating the effect of weight loss on thyroid function show inconsistent results. Whilst some authors have shown that weight loss after bariatric surgery may have a positive effect on thyroid dysfunction, especially in individuals with preoperative subclinical hypothyroidism 1 resulting in normalisation of TSH levels, others fail to show any significant postoperative changes.

Objective:

To evaluate the effect of dramatic weight loss after bariatric surgery on thyroid function (thyroid hormone levels and particularly morphological changes) in the short and long-term in the setting of a cross-sectional study. A particular focus will be made with regard to putting into correlation preoperative thyroid function abnormalities and postoperative changes over time with respect to the type of bariatric intervention carried out.

Methods:

BMI, thyroid hormones (TSH, fT3, fT4 levels), need for thyroxin substitution (or equivalent medication) as well as pre- and postoperative morphological changes in the thyroid gland (usually via sonography)and Leptin values will be assessed retrospectively.