What Are The Risk Factors For Developing Graves’ Disease?

Graves’ disease (GD) is an autoimmune condition characterized by an overactive thyroid (hyperthyroidism). Hyperthyroidism is usually followed by an accelerated heart rate. Some people also develop vision problems.

Graves’ disease affects 1%¹ of Americans and is the most common cause of hyperthyroidism.

Some people are more likely to develop Graves’ disease than others, including women and people with a family history of the condition.

Find out about the different risk factors for Graves’ disease and the early warning signs to watch out for.

How Graves’ disease develops

An increase in two thyroid hormones in the blood — triiodothyronine (T3) and thyroxine (T4)² — is the tell-tale sign of Graves’ disease. An excessive amount of these hormones are released when the thyroid gland is overstimulated, leading to hyperthyroidism.

The thyroid cells are stimulated when something specific binds with the receptors on the cell surfaces. This is usually thyroid-stimulating hormone (TSH). However, TSH receptor antibodies (TSHR antibodies) are structurally similar to TSH. They can also bind to these receptors to stimulate the cells.

TSHR antibodies are made in the thyroid gland. Without enough regulatory cells (suppressor T cells), TSHR production can become out of control.

When there are too many TSHR antibodies, more and more T3 and T4 thyroid hormones are released. This has two effects: the cells in the thyroid gland become enlarged and increase in number.

When this occurs, the thyroid gland becomes swollen, and you may notice a goiter (a noticeable lump in the front of your neck).

What are the risk factors for Graves’ disease?

When looking at what causes Graves’ disease, 79%³ are caused by genetic factors, and 21%³ are thought to be caused by environmental factors.

Specific risk factors for developing Graves’ disease include:

• Genetics

• Higher thyroid antibody levels

• Stress

• Being female

• High dietary iodine

• Pregnancy

• Smoking

• Other autoimmune conditions

• Infection

Genetics

Genetic causes of Graves’ disease have been studied in siblings and identical and non-identical twins. In these studies, researchers found that 35%⁴ of cases ran in families. This indicates there is a genetic link.

While you may be more likely to develop GD when passed down from your parents, researchers believe environmental factors⁵ trigger the condition.

Environmental factors

Several studies give strong evidence to suggest Graves’ disease often develops due to environmental triggers.

A study⁵ published in 2010 looked at partners and the prevalence of Graves’ disease. It found a high correlation, indicating environmental factors are a significant cause.

Reasons for this may include smoking habits or secondhand smoke inhalation, marital or relationship stressors, and infections. These risk factors may be shared between partners while they are together — at home, for example.

Stress

A study³ looked into stress, the hyperthyroid symptom scale (HSS), and circulating thyroid hormone levels (T3 and T4) in 263 people with Graves’ disease. Researchers found stress exacerbates hyperthyroidism symptoms.

Stress itself is generally not thought to trigger Graves’ disease, but researchers believe it contributes to the condition’s progression.

There is a possible explanation for this. With emotional stress, the hypothalamic-pituitary-adrenal axis (HPA) is activated, which stimulates the release of the stress hormone cortisol.

Chronic stress can cause the HPA axis to kick into gear even when there is no immediate stressful situation. This can result in prolonged HPA axis activation, which causes more cortisol to circulate around your body.

This cortisol increase affects your immune system, causing a sustained inflammatory response. When your immune system is constantly stimulated like this, it raises your risk of developing an autoimmune disease — like Graves’ disease.

Gender

Women have a higher lifetime risk of developing Graves’ disease than men.

The lifetime risk for women is 3%⁷. For men, it is 0.5%⁷.

Iodine levels

Iodine is an essential nutrient that’s vital for thyroid hormone production. It can be found in marine-derived food.

Thyroid hormone is needed for a fetus to grow. Research⁸ into iodine deficiency in land-locked areas without access to marine life found an increase in child developmental delays.

Iodine may be supplemented to combat iodine deficiency, but this has risks. If you live somewhere without iodine deficiency but supplement it or consume high amounts of iodine-rich foods (like kelp or seaweed), you may consume too much iodine.

Excess iodine in your body can injure your thyroid cells or cause them to die. In these cases, immune system cells accumulate in the area, causing inflammation.

The link between iodine and Graves’ disease is not always clear.

Iodine exposure is thought to be a risk factor for developing Graves’ disease, while latent Graves’ disease may be a risk factor for triggering iodine-induced hyperthyroidism.

However, some studies⁹ indicate iodine consumption is unrelated to Graves’ disease.

Pregnancy

Pregnancy may increase your chance of developing Graves’ disease. The Office on Women’s Health suggests women who have recently had a baby are seven times more likely to develop the condition.

Some women who become hyperthyroid during pregnancy are then diagnosed with Graves’ disease, as most cases of hyperthyroidism during pregnancy are caused by Graves’.

During pregnancy, the mother’s thyroid gland cells increase in number. This causes the thyroid gland to grow by 10 to 40%¹⁰. Thyroxine-binding globulin (TBG) and T4 hormone also increase from week four.

Hyperthyroidism during pregnancy may cause thyrotoxicosis if the condition is left untreated. Thyrotoxicosis is thought to cause pregnancy loss (miscarriage), raised blood pressure, low infant birth weight, limited growth, stillbirth, thyroid storm, and maternal heart failure.

Graves’ disease symptoms tend to decrease in the final months of pregnancy, but they may worsen again after delivery.

Smoking

Using nicotine products is a risk factor for developing Graves’ disease. It is also thought to increase your risk of developing Graves’ ophthalmopathy.

Research¹¹ has found the risk for developing Graves’ is higher in smokers than in non-smokers and that past nicotine use does not increase your risk of developing the condition.

Smoking as a risk factor is thought to be unrelated to iodine exposure.

Other autoimmune conditions

Around 17%¹² of people with Graves’ disease have other autoimmune conditions. It is thought that having another autoimmune condition may increase your risk of developing Graves’ disease.

Other autoimmune conditions are most often seen in people with Graves’ include:

• Type 1 diabetes

• Rheumatoid arthritis

• Vitiligo

• Multiple sclerosis

• Chronic autoimmune gastritis

Early signs of Graves’ disease

Graves’ disease is an autoimmune disorder linked to excess thyroid hormones. Because thyroid hormones have an effect on many other bodily systems and development (not just the thyroid gland), GD’s symptoms can be widespread.

Look out for the following common Graves’ disease symptoms:

• Chest pain, including palpitations, racing heart, or irregular heartbeat

• Insomnia

• Tremors

• Altered menstruation (irregular periods or none at all)

• Heat intolerance and sweating

• Restlessness

• Anxiety, depression, irritability, and general moodiness

• Fatigue

• Muscle weakness

• Reduced libido

• Eye symptoms include redness, dryness, tearing, bulging, and vision changes (Graves’ orbitopathy)

• Skin symptoms, including thickened, patchy pink skin over the lower legs and feet (pretibial myxedema)

The lowdown

Graves’ disease is a relatively common autoimmune condition involving the thyroid gland. It can cause a range of symptoms, including eye problems, skin problems, heart palpitations, heat intolerance, and even anxiety and depression.

Numerous risk factors, including genes, environmental factors, and emotional stressors, can play a part in the development of Graves’ disease.