Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

BACKGROUND: There is ongoing debate regarding the influence of minor changes in thyroid status within the normal range and body mass index (BMI). Overt thyroid dysfunction is well recognized to affect weight, but the influence of minor perturbations of thyroid function remains unclear. AIM OF THE STUDY: To examine in euthyroid subjects the association of serum concentrations of TSH and free T4 within the normal range and BMI. To compare serum TSH and free T4 concentrations in nonobese and obese subjects. SUBJECTS AND METHODS: A cohort of 401 euthyroid subjects with normal serum TSH (361 females, 40 males, mean age 48.2 years) who had been referred to a Thyroid Clinic due to the presence of a thyroid nodule or goitre. Measurements of serum TSH and free T4 were recorded, together with BMI (calculated from weight and height). Associations between measures of TSH, free T4 and BMI were investigated. RESULTS: There was no association between either serum TSH or free T4 concentration when considered as a continuous variable and BMI, and no difference in BMI when subjects were categorized according to serum TSH or free T4. There was also no difference in serum TSH or free T4 between lean and obese euthyroid subjects. Evidence of thyroid autoimmunity indicated by the presence of antibodies to thyroid peroxidase was likewise not associated with a difference in BMI. CONCLUSION: This study provides no evidence for an association between thyroid status within the normal range and BMI.

Original publication




Journal article


Clin Endocrinol (Oxf)

Publication Date





125 - 128


Antibodies, Body Mass Index, Cohort Studies, Female, Humans, Iodide Peroxidase, Male, Middle Aged, Obesity, Thyroid Gland, Thyroid Neoplasms, Thyroiditis, Autoimmune, Thyrotropin, Thyroxine