Apr 11 (HeartCenterOnline) - Researchers confirm an association between type 1 diabetes and thyroid disease. The results appear in the April 2003 issue of Diabetes Care.

Type 1 diabetes is also called insulin- dependent diabetes mellitus (IDDM) or juvenile-onset diabetes. It refers to a condition in which little or no insulin is produced by the pancreas (an organ next to the stomach). This is a rare and severe form of diabetes. It affects about 5 to 10 percent of all diabetics and develops before the age of 30. It is thought to be caused by a combination of genetic and environmental factors that results in a lack, or complete absence, of insulin. However, the reasons are largely unknown as to why the body's immune system attacks itself, destroying over 90 percent of its own insulin-producing beta cells in the pancreas.

High blood sugar levels can lead to a variety of symptoms (e.g., blurred vision) in the short-term, and serious consequences such as heart attack or stroke in the long-term. Other long- term consequences include permanent damage to the eyes, kidneys, nerves and blood vessels. A potentially fatal condition called ketoacidosis may also develop, in which the blood becomes increasingly acidic as toxic substances build up in the bloodstream.

Low blood sugar levels (hypoglycemia) can lead to a variety of symptoms, including sweating and dizziness. Severely low levels may also lead to shaking and/or fainting, which can be very frightening to both the patient and people around him or her. Although all people can be mildly hypoglycemic after not eating for several hours, diabetics can experience more severe hypoglycemia in a variety of common situations.

The current study noted that earlier reports found that individuals with type 1 diabetes had a risk two to three times greater than the general population for developing thyroid disease. The researchers wanted to "determine the natural history of thyroid dysfunction" in these individuals. Thyroid disease often has an autoimmune component, where the body's immune system attacks its own cells, resulting in a destruction of body tissue.

In 1983, 58 patients were enrolled in the Diabetes Control and Complications Trial at the University of Tennessee Health Science Center. For the next 18 years, these participants underwent regular thyro id testing. Eighteen patients had hypothyroidism. Also known as "underactive thyroid", hypothyroidism is a disorder in which the thyroid gland is not producing enough thyroid hormone to meet the body's needs. As a result, the patient may experience symptoms such as fatigue, weakness, lack of appetite and a low sex drive. The majority of people with hypothyroidism will need to take manufactured versions of natural thyroid hormones for the rest of their lives to relieve their symptoms and to avoid serious long-term consequences. These consequences include a greater risk for hardening of the arteries (atherosclerosis), heart disease, heart attack, high blood pressure (hypertension), stroke, respiratory problems and anemia.

Results showed that hypothyroidism was more common in female participants than in males. Among those participants in whom thyroid antibody tests revealed the presence of antibodies against several thyroid compounds, the likelihood of developing hypothyroidism was almost 18 times greater than patients who were negative for such antibodies.

The researchers recommend that individuals with type 1 diabetes "undergo annual screening by serum (thyroid stimulating hormone) measurement to detect... thyroid dysfunction."

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Hypothyroidism
Types of Diabetes

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