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Thyroid Disease and Diabetes: What You Need To Know

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A healthcare provider examines a patient's thyroid

Thyroid disease can occur with type 1 diabetes and cause symptoms such as fatigue and temperature sensitivity. 

It’s not uncommon for people with one autoimmune disease to develop other autoimmune conditions. 

For instance, the prevalence of celiac disease is higher among people with type 1 diabetes compared to the general population. Researchers don’t fully understand why this happens, beyond the fact that all autoimmune diseases share a common cause – they occur when the body attacks and destroys healthy tissue by mistake. 

Certain thyroid diseases are the most common autoimmune conditions associated with diabetes, according to the American Diabetes Association’s Standards of Medical Care. In addition, having autoimmune thyroid disease increases the risk of developing type 1 diabetes. 

The good news is that autoimmune thyroid disorders are straightforward to manage, according to experts. 

What is thyroid disease? 

The thyroid gland is a butterfly-shaped organ located at the base of the neck. It produces hormones that control the way your body uses energy. 

Thyroid hormones can affect heart rate, digestion, muscle function, and brain development. Thyroid disorders occur when the thyroid gland produces too much or too little thyroid hormones. 

Autoimmune conditions are the most common cause of thyroid disorders; other causes include infection, not getting enough iodine in your diet, and thyroid cancer. Thyroid disorders tend to be more common in women than men, both in the general population and in people with diabetes, though researchers don’t fully know why this is. 

There are two common autoimmune thyroid disorders: 

  • Hashimoto’s disease occurs when your body attacks the thyroid gland, causing it to produce too much or not enough thyroid hormones. With a shortage of hormones, your body’s functions may slow down (hypothyroidism). 
    • Symptoms of hypothyroidism include fatigue, constipation, dry skin, drowsiness/sluggishness, increased sensitivity to cold, and muscle weakness. 
  • Grave’s disease (hyperthyroidism) occurs when your body stimulates the thyroid gland, causing it to overproduce thyroid hormones. With elevated thyroid hormone levels, your body’s functions may speed up. 
    • Symptoms of excess thyroid hormones include weight loss, rapid or irregular heartbeat, sweating, diarrhea and/or frequent bowel movements, increased sensitivity to heat, and anxiety. 
    • Grave’s disease may eventually result in hypothyroidism after treatment for hyperthyroidism.

Thyroid disease and type 1 diabetes

While just 4% of the general population has thyroid disease, about 17-30% of those with type 1 diabetes are estimated to have a thyroid disorder. Both genetic and environmental factors are thought to contribute to the high rate of thyroid disorders among people with type 1 diabetes. 

“There is a strong relationship between autoimmune thyroid disease and type 1 diabetes since both are autoimmune conditions,” said Dr. Lynn Barbour, a professor of endocrinology, metabolism, and diabetes at the University of Colorado School of Medicine.

The ADA Standards of Care recommend all children diagnosed with type 1 diabetes be screened for thyroid-stimulating hormone (TSH), a measure of thyroid function, soon after their diabetes diagnosis. Screening for thyroid function should be repeated annually, and more frequently in people who develop symptoms or test positive for thyroid antibodies. 

Thyroid disease and type 2 diabetes

About 10-48% of people with type 2 diabetes are estimated to have thyroid disease. 

Research suggests that obesity may contribute to both hyperthyroidism and type 2 diabetes. Likewise, too much thyroid hormone may increase the risk of type 2 diabetes. A 2021 meta-analysis found that high levels of TSH were linked to a 17% higher risk for type 2 diabetes compared with normal levels of the hormone. 

Screening for thyroid disorders is not recommended by medical guidelines for people with type 2 diabetes. However, in clinical practice, providers commonly screen for thyroid diseases in everyone, including people with type 2 diabetes, said Dr. Elizabeth Buschur, professor at the Ohio State University Wexner Medical Center. 

“There can be a lot of reasons to screen for thyroid disorders,” Buschur said. “It’s definitely worth screening for thyroid disease when a patient has symptoms like fatigue, weight gain, or weight loss.”

Thyroid disease and gestational diabetes

A recently published study suggested that excess thyroid hormone might be linked to a greater risk of gestational diabetes (GDM). 

Analyzing data from nearly 27,000 pregnant women, researchers found that increased levels of TSH and mild hypothyroidism were linked to GDM. Based on these findings, researchers suggested that higher TSH levels in early pregnancy be considered a risk factor for GDM. 

Other research suggests that hypothyroidism (low thyroid hormones), particularly in the first trimester of pregnancy, is associated with an increased risk of developing GDM later in pregnancy. 

Since TSH affects insulin secretion, it may also be involved in the development of insulin resistance. However, researchers don’t fully understand the relationship between thyroid diseases and gestational diabetes

“There is really no clear reason for gestational diabetes to be related to thyroid disease since thyroid disease is due to autoimmunity and gestational diabetes is not an autoimmune disease,” Barbour said. 

“One speculation is that GDM and thyroid disease are both more common in women who are overweight and untreated thyroid disease might cause weight gain,” Barbour said. Specifically, hypothyroidism is associated with weight gain

Although there aren’t universal recommendations to screen for thyroid disorders in people who are pregnant, Buschur said that a family history of thyroid diseases and symptoms such as weight gain and fatigue can prompt screening in early pregnancy. 

It’s extra important to monitor thyroid hormone levels during and after pregnancy, Buschur said, as autoimmune activity often improves during pregnancy and then flares up postpartum. This pattern is especially common for people with hyperthyroidism, who may be able to stop taking thyroid medications during pregnancy but often need to resume their medications after giving birth. 

What to do if you have thyroid disease and diabetes

While juggling multiple endocrine disorders can be overwhelming, Buschur said that managing thyroid dysfunction is simpler than managing diabetes. 

1. Hormone replacement therapy 

Similar to taking insulin for diabetes, people with thyroid disease may need to replace missing thyroid hormone with levothyroxine. Most patients will need to continue taking thyroid hormone for the rest of their life.

Thyroid hormone is an oral medicine, taken once daily. Once you start taking the medication, your healthcare provider will check your thyroid function periodically. Your provider can also help monitor for other changes that can affect the dose of thyroid hormone, such as starting birth control, getting pregnant, undergoing menopause, or experiencing major weight gain or weight loss. 

2. Maintain a healthy weight

While thyroid dysfunction can cause weight gain and weight loss, research shows that obesity increases the risk of some thyroid disorders. Lifestyle factors, such as eating a nutritious diet and getting regular physical activity, are key to maintaining a healthy body weight. 

3. Manage blood glucose levels

Having an overactive thyroid has been linked to hyperglycemia (high blood sugar levels) and even diabetic ketoacidosis (DKA). On the other hand, having an underactive thyroid may be associated with insulin resistance and hypoglycemia (low blood sugar levels). 

Beyond thyroid disease, managing blood glucose levels is key to preventing other diabetes complications, like chronic kidney disease and peripheral neuropathy.

Managing thyroid disease can affect insulin needs and glucose metabolism in both type 1 and type 2 diabetes, Buschur said, so it’s important to know that you may need to adjust insulin doses as thyroid disease improves.

4. Learn how to cope with stress

Since many autoimmune diseases tend to “flare up” when people are stressed, Buschur said decreasing stress is key. Learning how to channel anxiety into something positive can be difficult, but there are different resources available to help you navigate these challenges. 

Some people may find that yoga, meditation, or movement helps them de-stress, while others may want to join a support group to meet others with shared experiences. 

The bottom line 

“In our patients with diabetes, we need to be looking for thyroid disease more often than in people without diabetes, because we know it’s more prevalent,” Buschur said.

Beyond the guideline recommendations, Buschur said that it’s a good idea to test for thyroid disease anytime someone with diabetes is “feeling off” and experiencing symptoms such as anxiety, temperature sensitivity, mood changes, or fatigue. 

Looking ahead, Buschur said that researchers are developing medications to address some of the symptoms of thyroid disease, such as fatigue, brain fog, and cold intolerance. Researchers are also working to understand the causes of thyroid disease and to investigate how sleep hygiene, depression, and anxiety impact thyroid disease. 

While managing thyroid conditions can affect insulin needs and glucose levels in both type 1 and type 2 diabetes, treatment can make a big impact. 

“Treating thyroid disease can make a huge difference in the way someone feels and their overall health,” Buschur said.

Learn more about diabetes and other autoimmune conditions: