Thyroid disease occurs more often in women and most commonly starts between 25 and 55 years of age. However, thyroid illness can occur at any age. The disease occurs as a result of an auto-immune process, when the body’s immune (defence) system becomes confused and attacks the thyroid as if it were not part of the body. A similar process occurs in Type 1 diabetes, when the immune system attacks and destroys the pancreas. Thyroid disease and diabetes may occur together in the same person. Both diseases affect the same age groups and both are common illnesses.
The thyroid is a butterfly-shaped gland found in the lower front of the neck. The thyroid consists of two ‘wings’ or lobes and a central connection called the isthmus. As the blood flows through the gland, cells extract iodine and enzymes change it into thyroid hormones. Years ago, an enlargement of the thyroid known as a goitre was often seen. The thyroid would grow very large in an attempt to capture as much iodine as possible. The Prairies were once known as the ‘goitre belt’. Iodine added to ordinary table salt has mostly eliminated this condition.
Either too much or too little thyroid hormone affects the metabolism and causes problems. For instance, when there is a lack of thyroid hormone, the bowel will move less frequently leading to constipation. Thyroid hormone excess can result in frequent, soft bowel movements. Heart rates can slow with too little, or speed up with too much, thyroid hormone.
With diabetes, there is an important balance between the rate at which energy (sugar) is used, the rate of transfer of energy (sugar) into the cells, and the intake of energy (food). Blood glucose levels rise or fall when one of these factors changes. Thyroid disorders affect the rate of energy use, the absorption of nutrients and the breakdown of medication. This can profoundly affect blood glucose levels.
In hyperthyroidism the thyroid gland produces and releases too much thyroid hormone. The body burns more energy since all the systems work at a faster rate. A faster metabolism can cause of variety of problems. Diarrhea may occur causing a loss of nutrients. Weight loss, with loss of muscle tissue, may occur. Fatigue may decrease activity and energy use. Medications may be broken down faster by the liver resulting in lower blood levels of medication. The medications may then not work as well as expected. As a result, blood glucose levels may rise or fall depending on which changes are more evident.
In hypothyroidism the thyroid gland does not produce enough thyroid hormone to run the body effectively. Metabolism often slows, leading to a slower burning of calories and weight gain. Energy levels fall so less activity occurs. Medications may build up as liver function slows. Blood glucose levels are affected by these changes.
The symptoms of thyroid disease are non-specific and may mimic those found in many other diseases. Thyroid disease has a hereditary component. The presence of thyroid disease in one or more family members makes it more likely that others in the family may develop thyroid disease. Symptoms that persist for weeks and months are also more likely to be of concern. Luckily, thyroid disease is easily diagnosed with a blood test. Treatment with medications can return thyroid levels back to their normal range.
Blood glucose levels can be affected by both hyperthyroidism and hypothyroidism. Thyroid disease may occur quickly or may start slowly. Changes in blood glucose levels, with no other cause, especially if other symptoms of thyroid disease are present, should be a clue to check for thyroid disease.