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Dr. Gupta answers: Can you discuss thyroid issues and the relationship to Type 2 diabetes?

I am a 56-year-old woman who has been diagnosed with Hashimoto's Thyroiditis. I have a vitamin D deficiency and I also have a genetic risk for type 2 diabetes. All of this is being monitored by blood work every three weeks, but I feel sometimes as if I correct one thing, it throws something else off (cholesterol, etc.).  I feel like I have to have a specialist for each aspect of this disease!

Can you discuss thyroid issues and the relationship to Type 2 diabetes and other issues?

The phrase "too many cooks in the kitchen" can sometimes apply to the world of medicine. It may be helpful to get a sub-specialist opinion on each topic but then bring all the ideas back together with a general internist or family practitioner who can help sort through all the recommendations and prioritize which to focus on first.

Much is known and much remains to be known regarding the relationship between the thyroid and diabetes. You may have heard the term “autoimmune” mentioned when hearing about the above diseases, but what does this term mean?

Autoimmune disorders are a diverse group of disorders that are caused by antibodies that get confused and attack the body’s own tissues. The disorder depends on what tissue the antibodies attack.

What are antibodies?

Antibodies are proteins that are produced by the body’s immune cells that attack and destroy bacteria and viruses that cause infections. Occasionally the antibodies get confused and attack the body’s own tissues, causing autoimmune disease.

Autoimmune thyroid disease is caused by antibodies that get confused and attack the thyroid. These antibodies can either turn on the thyroid (Graves disease, hyperthyroidism) or turn it off (Hashimoto’s thyroiditis, hypothyroidism). Other autoimmune disorders include type 1 diabetes mellitus. In type 1 diabetes the body’s immune system attacks and destroys the beta cells. Type 1 diabetes is caused by a lack of insulin due to the destruction of insulin-producing beta cells. Autoimmune thyroid disease is the most common autoimmune disorder associated with type 1 diabetes, occurring in anywhere from 17-30 percent of patients with type 1 diabetes. The American Diabetes Association recommends a screening blood test for thyroid disease soon after diagnosis of type 1 diabetes.

Type 2 diabetes is caused by a combination of factors

Type 2 diabetes, the most common form of diabetes, can be cause by insulin resistance, a condition in which the body’s muscle, fat, and liver cells do not use insulin effectively. Much remains to be known as to the association between this type of diabetes and the thyroid. A recent small study of interest used metformin, a diabetes drug that decreases insulin resistance, in patients with non-cancerous thyroid nodules. In this small study, metformin produced a significant decrease in nodule size within six months in patients who also had insulin resistance. This may suggest that insulin resistance may play a role in the development of thyroid nodules. The study is too small to recommend metformin for patients with thyroid nodules but indicates that more studies may be done in the future and reminds me of how many possible associations between diseases remain to be revealed to us in the ever developing field of endocrinology.