If you’ve been diagnosed with thyroid eye disease (TED), it’s normal to have questions about the condition. Although you can always call your doctor, you may want to do some research on your own, too. That way, you’ll be better informed the next time you follow up with your medical team.

People often want to know how common TED is and who is at risk of developing it. If you’ve never heard of it before, it’s normal to want to know how many other people are living with the same condition. Keep reading to learn more about TED.

How Many People Develop Thyroid Eye Disease?

TED is pretty rare. Doctors don’t know exactly how often it occurs. Some research shows that 19 out of every 100,000 people get it in the United States. Other studies say that between 90 and 300 out of every 100,000 people develop it. A study published in 2022 reviewed all of the available research on TED. It puts the numbers at 155 to 250 people out of every 100,000.

While uncommon, TED does not meet all of the criteria to be formally categorized as a rare disease.

TED may be less common in some places or among certain groups than others. This finding may help account for the differences in numbers. In the 2022 study, researchers noted differences in how common the condition is when it comes to living in different locations or coming from different ethnic backgrounds. It’s possible that TED is less common in the United States than it is in other areas, which could account for some of the difference in numbers.

Thyroid Eye Disease and Graves’ Disease

TED is linked to another autoimmune condition called Graves’ disease, which affects the thyroid gland. In Graves’ disease, the immune system mistakenly attacks the thyroid, often causing it to become overactive — a condition known as hyperthyroidism. This leads the thyroid to produce too much hormone, which speeds up many processes in the body.

Less commonly, Graves’ disease can lead to an underactive thyroid, or hypothyroidism. In this case, the thyroid makes too little hormone, slowing down body functions. Both hyperthyroidism and hypothyroidism can increase the risk of developing TED.

According to the Indian Journal of Ophthalmology, somewhere between 25 percent and 58 percent of people who are diagnosed with Graves’ disease will also develop TED. Other people may be diagnosed with TED without developing Graves' disease.

Who Gets Thyroid Eye Disease?

TED is more common in some populations of people than it is in others. Factors such as biological sex, smoking, genetics, and others can all influence a person’s risk.

Biological Sex and Thyroid Eye Disease

According to Cleveland Clinic, females are more likely to develop TED than males. It shows up in approximately 16 out of every 100,000 female births and in only 2.9 out of every 100,000 male births. This is likely because Graves’ disease is also more common in females, per Cleveland Clinic.

This difference may not be true for people of Indian and Malaysian ethnicity living in the country of their birth. In those populations, TED seems to show up similarly in males and females. However, these numbers may not be accurate because women in some regions of India and Malaysia use healthcare at a lower rate than men.

According to the National Organization for Rare Disorders (NORD), although males may be less likely to develop TED, they may be more likely to get a severe form of the condition. Thus, males need just as much monitoring and testing as females, and they may need different treatment options, as well.

Smoking and Thyroid Eye Disease

People who smoke are also more likely to develop TED. Different studies show different numbers, but someone who smokes cigarettes is somewhere between two and eight times more likely to be diagnosed with TED than those who don’t smoke. Researchers don’t know why smoking is a risk factor for thyroid eye disease, but they do know that quitting lowers your risk.

Genetics and TED

TED may have a genetic connection. You might be more likely to develop it if other people in your family have it.

Although Graves’ disease seems to have a genetic component, genes don’t seem to be the only cause. Doctors suspect that people may develop the condition when they have certain genes that are activated by certain viruses. Research is ongoing when it comes to how that works in the body and which viruses may activate the genes.

The genetic risk may not be for TED specifically. Instead, it may tie to autoimmune diseases in general. If someone in your family has another autoimmune condition, you may be at a higher risk for developing TED.

Age and Thyroid Eye Disease

Most people who have TED are diagnosed in middle age. The median age for diagnosis is 43, but people may be diagnosed much younger or much older than that. This finding ties in with Graves’ disease, which is usually diagnosed in people older than 30.

Vitamins, Minerals, and Thyroid Eye Disease

If you have low levels of selenium in your blood, you may be more likely to be diagnosed with TED. If you test low for selenium, taking supplements may help. However, these results are unclear. Some studies show that taking selenium supplements helps, while others don’t. You and your ophthalmologist or endocrinologist can talk about this and decide if trying supplements might be right for you.

Having low levels of vitamin D may also put you at a higher risk of developing TED. Research on vitamin D and its connection to TED is sparse, and more work is needed to figure out if taking more vitamin D could help. Again, you can talk to your healthcare provider to decide if taking supplements is right for you.

Other Conditions and Thyroid Eye Disease

A couple of other conditions may also be risk factors for developing TED. Diabetes is connected to certain eye problems, which may include TED. In some cases, diabetes is diagnosed soon after a diagnosis of TED. If you live with diabetes or suspect you might be developing it, talk to your endocrinology or ophthalmology team about whether testing for it is right for you.

Obstructive sleep apnea (OSA) may also be connected to TED. In OSA, a person’s breathing repeatedly stops and starts during sleep because their airway becomes blocked. A couple of studies indicate that having OSA can make TED worse. However, researchers need to do more work to establish this connection and understand how the two conditions might be related.

Talk to Your Doctor

If you want to understand more about TED, talk to your healthcare team. They should be happy to answer your questions so you have the information you need to take care of yourself.

Also ask your healthcare team about additional testing you might need. If you want to have your levels of selenium and vitamin D tested, they can help. They can also help you get testing for diabetes, sleep apnea, and genes tied to autoimmune disorders, Graves’ disease, and TED.

Talk With Others Who Understand

On TEDhealthteam, people share their experiences with thyroid eye disease, get advice, and find support from others who understand.

Are you wondering how common TED is? Let others know in the comments below.