NEW YORK (Reuters Health) - Individuals with celiac disease -- a common digestive problem in which the body cannot breakdown and absorb a protein found in wheat -- are at significantly increased risk for developing thyroid disorders, including hypothyroidism, hyperthyroidism and thyroiditis, investigators in Sweden have found.
The thyroid is a butterfly-shaped gland in the neck that produces hormones that regulate the body's metabolism. In hypothyroidism, the gland is underactive, causing symptoms such as fatigue, sensitivity to cold, dry skin and weight gain.
In hyperthyroidism, the gland is overactive, causing symptoms such as excessive sweating, heat intolerance, and nervousness. However, in mild cases of hypo- or hyperthyroidism no symptoms are present. Thyroiditis describes inflammation of the thyroid gland.
Using data from Swedish national registers, researchers led by Dr. Peter Elfstrom at Orebro University Hospital, studied the long-term risk of thyroid disease in more than 14,000 individuals diagnosed with celiac disease between 1964 and 2003 and some 68,000 age- and gender-matched control subjects without celiac disease.
They found that people with celiac disease had a greater than fourfold increased risk of being diagnosed with hypothyroidism, a threefold increased risk of suffering hyperthyroidism, and a 3.6-fold increased risk of developing thyroiditis.
The reverse was also true, with the same level of statistical significance, for an increased risk of celiac disease in people with established hypothyroidism, hyperthyroidism and thyroiditis.
"The association was seen in all strata (males, females, children, and adults)," the team notes in the Journal of Clinical Endocrinology and Metabolism, "and did not vanish after adjustment for potential confounders including the presence of diabetes mellitus."
"The positive association between celiac disease and thyroid disease may be due to shared genetic or immunological traits," the researchers say.
SOURCE: Journal of Clinical Endocrinology and Metabolism, October 2008.