BACKGROUND
Graves’ disease is the most common cause of hyperthyroidism in the United States. Up to 50% of patients with Graves’ disease develop involvement of the eye (thyroid eye disease – TED). While TED is most often seen in patients with Graves’ disease, it also can be seen in patients with Hashimoto’s thyroiditis. TED results from inflammation of the eyes, eye muscles and the surrounding tissues. Symptoms of TED can include dry eyes, red eyes, bulging of the eyes and double vision. The cause of TED is likely related to the antibodies that cause Graves’ disease that also bind to receptors on cells in the tissues around the eye and cause them to increase in size and number. Fortunately, the vast majority of patients with TED have mild disease requiring minimal or no treatment. However, moderate to severe TED is very serious and can significantly affect the appearance of the eyes and cause loss of vision. For severe TED, treatment options are limited.

A number of factors are identified that increase the risk of developing TED, including smoking, treatment with radioactive iodine, advanced age and poorly controlled hyper-and hypothyroidism. This study was performed to see if there were other factors associated with TED and, in particular, with progression to severe TED.

THE FULL ARTICLE TITLE
Lee, M et al 2020 Risk factors of thyroid eye disease. Endocr Pract 27:245–253. PMID: 33655885

SUMMARY OF THE STUDY
The study was done by identifying articles previously published in established databases that were original studies, written in or translated into English and examined the risk factors for TED.

Data was extracted from these articles and study populations were split into those with and without TED and those with active vs inactive TED. Information was examined regarding demographics (ie age, sex), characteristics of the study, patient comorbidities (other illnesses) and the details of the patients Graves’ disease.

The authors were able to extract data from 56 or 2228 articles initially identified. Of this group 14,052 had Graves’ disease without TED and 6051 had TED. Ages ranged from 28.6-50.9 years with TED occurring in 46% in women and 49% in men.

They confirmed that patients with TED were on average older than patients without TED, but found no difference in sex, family history, ethnicity or other illnesses.

When comparing patients with active vs inactive TED, again age was a risk factor as well as male sex and smoking history. In addition those with active TED were more likely to be current smokers than those with inactive TED (OR 2.78).

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study confirms that cigarette smoking and age are significant risk factors for developing TED. These factors as well as male sex were also associated with developing active TED. Since the major, modifiable risk factor is smoking, all patients with Graves’ disease who smoke should be encouraged to stop and those with TED should be aggressively counselled in smoking cessation.

— Marjorie Safran, MD, FACE

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