Endocrine Abstracts

Introduction: It is evident that hypothyroid patients have higher BMI than euthyroids. Until recently, much attention has been focused on finding whether minor abnormalities of thyroid function or differences in thyroid status of euthyroid subjects are related to body weight. Controversies, however, exist regarding the role of TSH in weight changes of euthyroid subjects.

Objective: The aim of this study, the Tehran Thyroid Study, was to determine any possible relationship between thyroid function tests and BMI in euthyroid subjects.

Material and methods: From the cross sectional phase of the Tehran Lipid Glucose Study (TLGS), a population based study of 15 005 participants, 1107 euthyroid subjects (506 male and 601 female, mean age of 37±8 years) with normal serum TSH (0.4–3.5 mU/l), aged over 20 years, were randomly selected. Multiple linear regression analysis was used to investigate the role of TSH in BMI changes, after adjustment for confounding factors.

Results: After adjustment of age, sex and physical activity, no significant relationship was found between serum TSH concentration and BMI (r=0.7, P=0.1); results were the same in men and women. Subjects were divided through categories of TSH (low 0.4–0.9 mU/l, middle 1–1.9 mU/l and upper 2–3.5 mU/l tertiles) and the median BMI was found to be similar in all three groups (26.5, 26.9, 27.3 kg/m² respectively).

Conclusion: No association was found between thyroid status and BMI in euthyroid subjects.