People with rheumatoid arthritis may have an increased risk of other autoimmune conditions, including hypothyroidism. Likewise, those with autoimmune hypothyroidism may be at an increased risk of rheumatoid arthritis.

Hypothyroidism refers to an underactive thyroid gland. In other words, it involves the thyroid not producing enough hormones for your body’s needs.

In some cases, hypothyroidism is caused by an autoimmune response. This is when the immune system mistakes the body’s tissues for dangerous intruders and attempts to destroy them. Autoimmune thyroid disease is a known risk factor for other autoimmune conditions.

Rheumatoid arthritis (RA) is another autoimmune condition in which the immune system mistakenly attacks healthy cells in the joints. Symptoms include joint stiffness and pain, often starting in the joints in the hands and feet.

Hypothyroidism and RA frequently co-occur and raise the risk of each other. The two conditions may also manifest with similar symptoms.

People with rheumatoid arthritis appear to have an increased risk of developing other autoimmune conditions, including hypothyroidism, and the reverse also seems to be true.

In general, having any autoimmune condition increases the chance of other autoimmune disorders, so this link is not exclusive to those living with RA and autoimmune hypothyroidism.

Increased risk of hypothyroidism in people with rheumatoid arthritis

In a 2022 study, researchers analyzed the Taiwan National Health Insurance Research Database to examine the risk of hypothyroidism in people with rheumatoid arthritis.

The researchers found that those with an RA diagnosis were 1.74 times more likely to eventually develop hypothyroidism than people without RA. They also found that the association was particularly high in females and older adults.

In a 2023 study, researchers analyzed the relationship between these two conditions in people of European descent. They found an increased risk (1.28 times) of hypothyroidism and an increased chance (1.12 times) of secondary hypothyroidism in people with RA.

Secondary hypothyroidism occurs when the pituitary gland or hypothalamus is underactive, causing the thyroid gland to underproduce hormones.

Read about other health conditions associated with RA.

Increased risk of rheumatoid arthritis in people with hypothyroidism

People with a diagnosis of hypothyroidism seem more likely to eventually develop rheumatoid arthritis and have more severe symptoms.

In the same 2023 study mentioned above, researchers found that people with hypothyroidism had a higher risk (1.68 times) of developing RA. People with secondary hypothyroidism had a 1.74 times higher risk.

In another study using data from Sweden, researchers found that 10.3% of people with RA had autoimmune thyroid disease at the time of their diagnosis compared with 7.1% of people without RA. The risk of autoimmune thyroid disease increased during the 5 years before an RA diagnosis and decreased 2 to 5 years after diagnosis.

A growing body of recent research also suggests that people with autoimmune thyroid disease are at an increased risk of developing more severe RA symptoms. Autoimmune thyroid disease may also worsen the following:

Hypothyroidism and rheumatoid arthritis may manifest with overlapping or similar initial symptoms, including:

When hypothyroidism causes joint symptoms, these are most likely to manifest in your:

  • knees
  • hands and wrists
  • feet

RA also affects the joints in your hands, wrists, or feet. It may manifest in other joints as well.

Other symptoms of hypothyroidism may include:

Additional symptoms of RA can include:

  • fever
  • sweating even in the absence of high temperatures
  • poor appetite and weight loss
  • chest pain

Rheumatoid arthritis is an autoimmune condition. Experts have not established what causes it, but possible risk factors include:

  • certain genes passed through families
  • being female, as females have a two to three times higher risk than males
  • tobacco use

The most common cause of hypothyroidism is an autoimmune condition known as Hashimoto thyroiditis.

Other causes of hypothyroidism may include:

  • inflammation of the thyroid (thyroiditis)
  • thyroid birth defects
  • absence of the thyroid (by surgical removal)
  • radiation treatment for your thyroid
  • some medications
  • too little iodine in your diet
  • pituitary or hypothalamus issues

Those at a higher risk of developing hypothyroidism include:

  • females over 60 years old
  • adults with a history of head or neck radiation therapy
  • people with other autoimmune disorders
  • people with type 1 diabetes (another autoimmune condition)
  • adults with a family history of thyroid disease, such as Graves’ disease or Hashimoto thyroiditis

Getting a positive result for the thyroid peroxidase antibody test usually means you have Hashimoto thyroiditis. The test detects levels of specific types of thyroid antibodies that signal an autoimmune attack on the thyroid gland.

Having any autoimmune condition is a risk factor for both RA and Hashimoto thyroiditis.

Hypothyroidism is usually treated with levothyroxine, a drug that replaces the hormone your thyroid isn’t producing. Once you start the medication, you’ll likely receive regular blood tests to track your thyroid hormone levels, as it can take a while to find the dosage that relieves your symptoms.

Rheumatoid arthritis is treated with medications to reduce autoimmune activity and manage pain. These may include:

Can you have rheumatoid arthritis and hypothyroidism at the same time?

Rheumatoid arthritis and hypothyroidism can and often occur together. Developing one condition puts you at an increased risk of developing the other one. RA and hypothyroidism also share some symptoms, like joint pain and fatigue, which could sometimes lead to a misdiagnose.

Do rheumatologists treat thyroid problems?

Rheumatologists are usually aware of hormonal problems that can lead to joint pain and inflammation. It’s not uncommon for a rheumatologist to diagnose and treat thyroid problems.

Can thyroid problems cause rheumatoid arthritis?

Thyroid disease doesn’t directly cause rheumatoid arthritis, but it may increase your risk of developing it due to factors such as shared genes and a predisposition to autoimmunity.

What do your hands look like if you have hypothyroidism?

Not everyone with hypothyroidism experiences changes in their hands. For some people, hypothyroidism may lead to joint pain in your hands. Other changes are possible, including brittle nails or vertical white ridges on your nails. Joint swelling in the hands may be a sign of other conditions and medical attention is highly advised.

People who have either hypothyroidism or rheumatoid arthritis seem to be at an increased risk of developing the other. Factors such as shared genes and a predisposition to autoimmune disease may play a role.

Both conditions can cause joint pain and symptoms such as fatigue or weight gain. Hypothyroidism is primarily treated with medications to replace missing thyroid hormone levels. RA is usually treated with medications to reduce immune activity, improve inflammation and pain, and improve other symptoms.