The relation between thyroid-stimulating hormone and measures of adiposity in patients with manifest vascular disease

Visceral adiposity is associated with cardiovascular risk factors and increased cardiovascular risk. Thyroid-stimulating hormone (TSH) levels in the normal range are associated with a higher risk of fatal coronary artery disease. We hypothesize that TSH levels in the normal range are associated with an increase in visceral adipose tissue (VAT) in patients with vascular diseases.

In 2419 patients with vascular diseases, visceral fat thickness was analysed with ultrasonography. The association between TSH and VAT was quantified using linear regression analysis. Results are expressed as beta (β) regression coefficients with 95% confidence intervals. Adjustments were made for age, sex, current smoking and weight. Separate analyses were performed per quartile of age.

β-coefficients for the relation between TSH and VAT (change per SD of 2·55 cm) was 0·085 (95% CI 0·012-0·157) in the highest quartile of age (range 67-80 years) when adjusted for age, gender and current smoking and remained statistical significant after further adjustment for weight (β 0·096 95% CI 0·034-0·157). Per SD change, the β-coefficient for TSH and VAT tissue was larger than for other measures of adiposity.

In conclusion, higher TSH plasma levels in the normal range are associated with more VAT in patients with manifest vascular disease above the age of 66 years. No association was found between plasma TSH levels and weight or BMI. The relation between TSH levels and VAT may provide an explanation for the increased cardiovascular risk associated with elevated TSH plasma concentrations within the normal range.