Thyroid and Diabetes

If you have type 1 diabetes, there is a good chance you may also be at risk for another autoimmune disease.  Approximately one-third of type 1 patients have markers for another autoimmune disease at diagnosis.

One of these diseases is thyroid disease.  Thyroid disease is common in the general population, but it is especially common in type 1 women with more than 20% having the disease.  Many people with type 2, in particular middle-aged women, are also susceptible to a non-immune-based form of thyroid disease.

The thyroid, a small, butterfly-shaped gland that wraps around your windpipe, has a highly important job. As the largest gland in the endocrine system, it regulates hormones and ensures growth, metabolism and development all occur at “normal” rates.

When the thyroid gland is out of synch, its regulative functions are thrown off. The hormonal imbalance can result in either hyperthyroidism or hypothyroidism.

Hyperthyroidism is caused by the thyroid gland producing too much thyroid hormone.  It may be caused by Graves disease (an autoimmune disease in which the body’s own cells attack the thyroid gland), one or more thyroid nodules, ingesting too much iodine, inflammation of the thyroid gland or taking too much thyroid medication.

Symptoms include:

  • Sweating
  • Weight loss
  • Diarrhea
  • Distraction
  • Menstrual changes in women
  • Rapid heart rate
  • Thick skin on the knees, elbows, and shins

When you have hyperthyroidism your metabolism quickens, and medicines such as insulin are metabolized faster. Your blood glucose level may appear higher than usual because the insulin or oral medications do not remain in the body long enough to control it.  In addition, the symptoms of hyperthyroidism may mimic those of hypoglycemia.  It is important always to check your blood sugar before eating extra carbohydrate.

Hypothyroidism is caused by thyroid gland producing too little thyroid hormone.  The most common form of hypothyroidism is an disease called Hashimoto’s thyroiditis.  Symptoms include:

  • Fatigue
  • Lethargy
  • Depression
  • Constipation
  • Weight gain
  • Low blood pressure
  • Slow pulse
  • Intolerance to cold

Hypothyroidism causes your metabolism to slow and the medications you take, including insulin, stay active longer than they normally would.  You may find that your blood glucose levels are lower than they are normally, and you may experience hypoglycemia or low blood sugar.  Until the condition is treated it may be necessary to reduce your dose of insulin or oral medication to prevent low blood glucose.

It’s important to have your thyroid levels checked annually with a simple a blood test. The test will indicate whether you have an over-active or under-active thyroid, depending on the level of hormones in your blood. Your doctor can take it from there and put you on a proper course of medication, to get your hormones under control without affecting greatly your diabetes.

And because thyroid disease is common in type 1 if you experience any of the above symptoms it is important to inform your health care provider so you can receive the proper treatment for both diseases.

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  1. I have been a Type 1 diabetic for 30 years and developed Graves Disease after the birth of my daughter almost 18 years ago. I now have hypo and have gained probably 100 lbs. since. I want some of the Graves disease back. lol. I wonder if that makes me more susceptible to other autoimmune diseases or if I am at risk for RA or some other disease. Does anyone know of additonal risks for other autoimmune diseases?

  2. Good article and relevant to me personally but as someone who works at a dental clinic in Connecticut I’d be very interested to hear your view on the purported link between hyperthyroidism and halitosis, gum disease and other forms of dental issues. Thanks!

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