Is there any relationship between thyroid gland and blood sugar

Whether the thyroid hormone is secreted too much or too little, it will affect blood sugar. Even some thyroid diseases will affect the metabolism of blood sugar in the body. The reason why the thyroid gland affects the metabolism of blood sugar is mainly because the thyroid gland and pancreatic islets are both endocrine organs and have a hormonal balance relationship with each other. The pancreatic islets are precisely the organs that break down and produce blood sugar. Therefore, the thyroid gland will affect the blood sugar content in the human body.

(1) Hyperthyroidism

Patients with hyperthyroidism often have abnormal glucose metabolism or diabetes, with an incidence of approximately 1.7% to 65.0%. The severity, course of hyperthyroidism and underlying diseases are the fundamental factors affecting glucose metabolism results.

In hyperthyroidism, thyroid hormones have a dual effect on pancreatic function, changing the body's sensitivity to insulin and accelerating insulin degradation. When thyroid hormones increase, pancreatic B cell function decreases and the amount of substances antagonizing insulin increases. Therefore, patients with hyperthyroidism should undergo routine glucose metabolism tests and follow up regularly. Some patients can further screen for insulin after glucose load and autoimmune-mediated diabetes-related antibodies.

The symptoms of hyperthyroidism with diabetes may be confused with the hyperglycemic and hyperosmotic state and are easily overlooked; when receiving insulin treatment, the amount of insulin used will be greater than the actual need.

(2) Hypothyroidism

Hypothyroidism itself can improve hyperglycemia, but the mechanism is still unclear and related research is limited. In contrast to hyperthyroidism, hepatic glucose output, gluconeogenesis, and peripheral glucose utilization are all reduced in hypothyroidism. Animal experiments have found that the gastrointestinal absorption of glucose is slowed down in hypothyroid mice, thereby improving hyperglycemia.

The glucose conversion in patients with hypothyroidism is reduced, suggesting that these patients are prone to hypoglycemia, which may be due to the slowing of systemic metabolism. In clinical work, we need to be alert to the risk of hypoglycemia.

(3) Thyroid nodules

Diabetes can cause abnormal secretion of multiple endocrine hormones such as thyroid hormones, resulting in a higher incidence of thyroid nodules in diabetic patients than in the general population. But there is no need to panic, as most thyroid nodules are benign and only a few are malignant.

The degree of insulin resistance is also related to the occurrence of thyroid nodules, because insulin resistance can lead to increased compensatory insulin secretion. Insulin itself is also a thyroid growth factor that can induce the growth and proliferation of various cells including thyroid cells, thereby causing abnormalities in thyroid function and structure.

On the other hand, insulin affects the morphology of the thyroid gland. The incidence of thyroid nodules in people with insulin resistance increases, and the size of nodules increases. Adults with type 1 diabetes and abnormal thyroid ultrasound often show abnormal low-echo thyroid morphology and a larger size than that of healthy people.

Older age, obesity, high fasting blood sugar and being female are risk factors for diabetes and thyroid nodules, and clinicians should take this into consideration.