New Study Examines Celiac Disease and Hypothyroidism
Researchers Look at Whether Celiac Disease Affects Absorption of Levothyroxine
Celiac disease is common among patients who have hypothyroidism. However, in this population, malabsorption of levothyroxine has not been studied. Researchers investigated whether levothyroxine dosing is affected by the presence and treatment of celiac disease.
They published their findings in an article in the March 2012 issue of The American Journal of Medicine. Their article was called “Celiac disease and hypothyroidism.” The research team did a retrospective study at an academic medical center. Participants in their study were divided into 2 groups—the case group and the control group.
Participants in the case group had both hypothyroidism and celiac disease. Researchers determined whether the participants had celiac disease by using representative pathology with positive serology. They identified celiac disease in 152 of the study participants, and 22 participants also had hypothyroidism (14.5%). The researchers identified 7 participants in the case group who met the inclusion criteria.
Participants in the control group just had hypothyroidism, and they were selected randomly through endocrinology clinic records. Overall, the researchers identified 200 control participants.
The following were assessed for participants in both groups:
- Body mass index
- Medical co-morbidity
Researchers evaluated the levothyroxine dose and weight-based levothyroxine dose necessary to maintain euthyroidism for those in the control group. They also looked at the levothyroxine dose necessary to maintain euthyroidism before and after treatment for celiac disease for those in the case group.
All participants in the case group initially needed at least 125 μg of levothyroxine to maintain euthyroidism.
They found that the mean levothyroxine dose before being treated for celiac disease and weight-based levothyroxine dose necessary to maintain euthyroidism were higher in those in the case group than in those in the control group (154 μg vs 106 μg; p=.007; and 2.6 μg/kg vs 1.3 μg/kg; p<.001).
In addition, they found that levothyroxine doses were significantly reduced after the participants were treated for celiac disease (154 μg vs 111 μg; p=.03; and 2.64 μg/kg vs 1.89 μg/kg; p=.04).
The research team concluded that malabsorption of levothyroxine is possible for patients who have both hypothyroidism and untreated celiac disease. They determined that proper absorption of levothyroxine may improve after patients with hypothyroidism and untreated celiac disease are treated for celiac disease. Additionally, they recommend that screening for celiac disease in patients who have hypothyroidism and who require increased levothyroxine doses merits additional investigation.