Endocrine Abstracts

The objective of the study was to investigate association between BMI, waist circumference, and measures of thyroid function among euthyroid adult women.

Material and methods: We analysed retrospective data of 119 euthyroid women participating in Lithuanian screening and prevention program for patients with high cardiovascular risk at Vilnius Antakalnio Outpatient Clinic from Jul 2013 to Dec 2013. Glucose, lipid profile, TSH, and fT₄ tests and ultrasound of thyroid gland records were investigated and thyroid gland volume was calculated using formula: thyroid volume=height×width×depth×correction factor (as 0.524).

Results: Mean patients age was 57.04±4.56, BMI 28.86±5.53 kg/m², waist circumference 88.40±12.24 cm, TSH 1.81±0.92 mIU/l, fT₄ 12.84±2.89 pmol/l, and mean thyroid gland volume 14 464.46±6453.74 mm³. 36.1% of women were obese and 41.2% overweight. Mean TSH and thyroid volume did not differ between groups of obese, overweight and normal weight women. TSH inversely correlated with thyroid gland volume (r=−245, P=0.044), fT4 (r=−0.471, P=0.042), and positively correlated with waist circumference (r=0.210, P=0.036) and BMI (r=0.184, P=0.045). After adjusting for age, presents of diabetes and dyslipidaemia significant positive association was observed between TSH and waist circumference (B=0.17, P=0.029).

Conclusions: We found that measures of overall and central adiposity were associated with higher circulating levels of TSH in euthyroid women. Although, weight loss and weight gain are well-known consequences of overt thyroid dysfunction, our results suggest that, within the euthyroid range, excess body weight and especially central obesity may induce changes in thyroid hormone levels.