Increased Risk of Type 1 Diabetes in People with Celiac or Thyroid Disease: A Summary of a New Observational Study (+Video)

Celiac.com 07/17/2025 - People living with autoimmune conditions often face higher risks for developing other autoimmune diseases. One such concern is type 1 diabetes, a serious and lifelong condition where the immune system destroys insulin-producing cells in the pancreas. This new observational study explored whether people with celiac disease or thyroid disorders—two common autoimmune conditions—are at a higher risk of developing type 1 diabetes compared to those without these conditions. The findings offer valuable insights that may influence how patients are monitored and cared for after being diagnosed with one autoimmune disease.

How the Study Was Designed

This was a large-scale, retrospective observational study using health insurance claims data from millions of people in the United States. The researchers compared individuals diagnosed with celiac disease, hyperthyroidism (such as Graves' disease), or hypothyroidism (such as Hashimoto's disease) to similar individuals who had none of these conditions. The goal was to see how many in each group went on to develop type 1 diabetes.

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To ensure fairness in comparison, each person with a condition of interest was matched to a control person based on age, sex, and other health characteristics. This approach helped reduce bias and made the results more reliable.

Participants were followed for at least one month and up to several years, with most people being followed for about two years. The researchers looked for new diagnoses of type 1 diabetes in both the disease groups and the control groups during this time.

Key Findings: Celiac and Thyroid Disease Raise the Risk

The results clearly showed that people with any of the three autoimmune conditions had a significantly higher risk of developing type 1 diabetes compared to those without these conditions:

• Celiac disease: 0.14% of individuals developed type 1 diabetes, compared to only 0.06% of the matched controls. This means the risk was more than twice as high.
• Hyperthyroidism: 0.17% developed type 1 diabetes vs. 0.06% of controls—nearly a threefold increase in risk.
• Hypothyroidism: 0.18% developed the disease, compared to 0.08% of controls, more than doubling the risk.

In particular, children and teenagers (under age 18) were at even greater risk. For young people with hyperthyroidism, the risk of developing type 1 diabetes was more than eight times higher than in peers without the condition. Similarly, those under 18 with hypothyroidism had over three times the risk, and those with celiac disease had about triple the risk.

Time to Diabetes: Faster Onset in Autoimmune Groups

Not only were people with these autoimmune conditions more likely to develop type 1 diabetes, but they also developed it faster. For example, people newly diagnosed with celiac disease developed type 1 diabetes in just over a year, on average. This rapid progression raises concern because type 1 diabetes often presents suddenly and can result in serious complications like diabetic ketoacidosis if not caught early.

Why These Results Are Reliable

The researchers performed multiple tests to ensure their findings were solid. They analyzed not only people newly diagnosed with autoimmune conditions but also ran a secondary test that required evidence of both a diabetes diagnosis and insulin use—confirming the need for insulin therapy. These extra layers of analysis supported the original findings and showed that the results were consistent across age groups and not dependent on family history of type 1 diabetes.

Even people without a relative with type 1 diabetes still had a significantly higher risk if they had celiac or thyroid disease. This challenges the assumption that only people with a family history should be closely monitored.

What This Means for Celiac Disease Patients

For individuals with celiac disease, this study is particularly meaningful. While it's known that celiac disease and type 1 diabetes often occur together—especially in children—this study quantifies the risk in a large population of both children and adults. It also highlights how quickly type 1 diabetes can develop in this group. Importantly, the findings suggest that people with celiac disease—even without a family history of diabetes—should be considered for early screening to detect signs of type 1 diabetes before symptoms appear.

The Role of Screening and Early Detection

One of the key takeaways from this study is the importance of screening. Type 1 diabetes does not appear overnight. It develops gradually, beginning with the appearance of certain autoantibodies in the blood. These early warning signs can be found long before blood sugar levels rise or symptoms show up. By identifying people in the early stages, doctors may be able to delay or even prevent the full onset of the disease using new therapies now in clinical trials.

Yet, current guidelines often do not recommend routine diabetes screening for people with other autoimmune diseases unless they have a close relative with type 1 diabetes. This study provides strong evidence that such guidelines may need updating.

Limitations to Consider

As with any research, there are some limitations. This study used insurance claim data, which depends on accurate diagnosis codes. Errors in medical coding or differences in how diseases are diagnosed could influence results. Also, since the study used U.S.-based insurance data, the findings might not apply directly to people in other countries with different healthcare systems.

Another challenge is that the exact autoimmune cause of thyroid disease wasn’t always clear in the data. Graves' disease and Hashimoto’s disease were likely included but not specifically separated from other types of thyroid dysfunction. Still, the large number of participants makes the findings significant.

Conclusion: Why This Study Matters for People with Celiac Disease

This study shows that people with celiac disease are more than twice as likely to develop type 1 diabetes as those without it—and that risk may be even higher in children. The same is true for individuals with thyroid disorders. These findings provide a strong argument for routine screening for early signs of type 1 diabetes in people with these conditions, regardless of family history.

For those living with celiac disease, this means being aware of possible symptoms of diabetes, such as increased thirst, frequent urination, or unexplained weight loss, and discussing screening options with their healthcare provider. With earlier detection, there is a greater opportunity to avoid severe complications and possibly benefit from therapies that slow disease progression.

Ultimately, this research may help shape future guidelines to better protect individuals at risk—and ensure those living with one autoimmune disease do not face the surprise of another.

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