Endocrine Abstracts

Introduction: Selenium supplementation is recommended for all patients with mild Graves’ orbitopathy (GO). The thyroid gland contains high levels of selenium, which has an anti-oxidant effect and a role in the metabolism of thyroid hormones. The study on which this recommendation is based was conducted in countries of a selenium-deficient region and did not measure subjects’ selenium concentrations. There is therefore no consensus on optimum dose, duration, or safety. Environmental selenium varies extensively between countries and no published studies report measured the baseline selenium status of UK GO patients. We aimed to determine baseline selenium status in a UK population, and compare this to Graves’ patients without GO.

Methods: Baseline serum selenium status was measured in UK Graves’ disease patients with and without orbitopathy between January – December 2021.

Results: There were 56 patients; 25 had orbitopathy (the mean Clinical Activity Score was 1.9), (20 females and 5 males, average age 48.8yrs) and 31 did not (26 and 5; 47.5). Average serum selenium was 1.13 (range 0.5-1.93, reference range 0.76-1.46 μmol/l); 1.14 in the GO group vs. 1.12 in the non-GO group. There were 12 current or previous smokers in the GO group (48%) vs. 8 in the non-GO group (26%).

Conclusion: These results show that baseline selenium status in GO and non-GO patients is largely within the normal range. This suggests that selenium may have lesser benefit in the UK compared to regions with lower environmental selenium. Patients may also be at risk of iatrogenic overdose. A randomised control trial investigating the clinical effects of selenium supplementation in a UK GO population with concurrent measurement of selenium status is warranted.