The thyroid gland is located in front of the trachea, shaped like a butterfly and resembling a shield, hence its name. Specifically, it lies about 2–3 cm below the Adam’s apple and moves up and down with swallowing. That is why clinicians often ask patients to swallow during a thyroid examination.
Thyroid disorders mainly include hyperthyroidism, hypothyroidism, thyroid nodules, thyroiditis, goiter, and in more severe cases, thyroid cancer.
Why Are Diabetic Patients Prone to Thyroid Diseases?
Diabetes and thyroid diseases are the two most common endocrine disorders. Although they often occur independently, scientists have observed a striking pattern:the prevalence of thyroid disease is much higher in diabetic patients than in non‑diabetic individuals.
For example:
The prevalence of thyroid disease in the general population is about 7%.
In people with type 2 diabetes, it rises to 12%.
In those with type 1 diabetes, it increases further to 33% — meaning nearly one in three patients with type 1 diabetes may have a concurrent thyroid disorder.The exact reason remains unclear, but experts believe the two conditions may share common immunogenetic origins.
Type 1 diabetes is an autoimmune disease in which the immune system mistakenly attacks the body’s own tissues, especially pancreatic beta‑cells, leading to their dysfunction.Similarly, certain forms of thyroid disease also result from autoimmune dysfunction, where the immune system attacks the thyroid gland.People who develop one autoimmune disease are generally more likely to develop others, which helps explain the high co‑occurrence in type 1 diabetes.
In addition, type 1 diabetes and autoimmune thyroid diseases share common genetic susceptibility genes.
The association between thyroid disorders and type 2 diabetes is less pronounced. Proposed mechanisms include:
Thyroid hormones contribute to the development of type 2 diabetes by increasing insulin resistance.
Hyperthyroidism impairs glucose tolerance and raises insulin requirements.Which Thyroid Diseases Are More Common in Diabetic Patients?
Type 1 diabetes is more frequently associated with hyperthyroidism, hypothyroidism, and thyroiditis.
Type 2 diabetes is more often complicated by hypothyroidism and subclinical hypothyroidism.Thyroid disease is more common in women, and the same applies to diabetes combined with thyroid disease.
Harm of Diabetes Combined With Thyroid Disease
When the two conditions coexist, they interact and worsen each other:
Diabetic patients with hypothyroidism have a significantly higher risk of atherosclerosis, possibly related to autoimmune inflammation.
Hyperthyroidism aggravates metabolic disturbances, increases insulin demand, promotes the development of complications such as ketoacidosis, and raises the risk of cardiovascular events.Should Diabetic Patients Be Screened for Thyroid Disease?
Due to the high comorbidity and mutual exacerbation, many international diabetes guidelines recommend regular thyroid screening for early detection and treatment.
For instance:
The American Thyroid Association suggests that diabetic patients aged 35 years and older undergo thyroid function testing, with repeat screening every 5 years for all adult diabetic patients.
Other guidelines recommend checking TSH and thyroid antibodies in pregnant and postmenopausal women with diabetes.TSH (thyroid‑stimulating hormone) is the most representative marker for evaluating thyroid function.