According to the National Institutes of Health, as of 2008, approximately 140,000 people in the United States had been diagnosed with celiac disease. But as many as 3 million people in the U.S. may be suffering from it without knowing.
Research from 1963 to 2003 at the Orebro University Hospital in Sweden indicated that people with celiac disease had a higher than normal risk of developing thyroid disease. Hypothyroidism was four times more common in celiacs than in non-celiacs. Hyperthyroidism was three times more common in celiacs than in non-celiacs.
Researchers speculate that shared genetics or shared immunological characteristics may be factors in this apparent link between thyroid disease and celiac disease. This data was published in the October, 2008 edition of the Journal of Clinical Endocrinology and Metabolism.
In an October 2007 PubMed article, a connection between celiac disease and autoimmune thyroid disease was reported.
Autoimmune thyroid disease and celiac disease have been seen to have similar HLA haplotypes. HLA stands for human leukocyte antigen. Human leukocyte antigens are proteins that aid in the immune system's ability to differentiate between the body's cells and foreign substances.
Haplotypes are a combination of alleles from different genes within the same chromosome and usually inherited together.
They have both been associated with the gene encoding cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4). Research suggests that this gene may make its unfortunate owner more vulnerable to autoimmune disorders.
Based on these findings, the NIH has advocated the screening of people who have autoimmune diseases like autoimmune thyroid disease because these people are also at higher than normal risk for celiac disease. A gluten-free diet has been seen to improve the ability to absorb medication for hypothyroidism.
Celiac disease, which does not display any overt symptoms, is called silent celiac disease. A link is seen between silent celiac disease and autoimmune thyroid diseases.