OBJECTIVE: To investigate the prevalence of thyroid dysfunction and autoimmunity in type 2 diabetic patients.

METHODS: The study was conducted at the National Center for Diabetes, Endocrinology and Genetics, Jordan University Hospital, Amman, Jordan, between March 2000 and September 2000. A group of 908 type 2 diabetic patients (T2DM) were recruited in the study and underwent investigations for thyroid functions; free thyroxine (FT4), free tri-iodothyronine (FT3) and thyroid stimulating hormone (TSH). Six hundred had performed thyroid autoantibodies, thyroid peroxidase antibodies (TPOab) or antimicrosomal antibodies (AMA) and thyroglobulin antibodies (Tgab). They were compared with 304 non-diabetics, of those 282 had performed thyroid antibodies.

RESULTS: Fifty-three (5.9%) of diabetic patients were known to have thyroid disease. As a direct result of screening, new thyroid disease cases were diagnosed in 6.6% of the patients. Thus, the overall prevalence of thyroid disease was found to be 12.5%. The most common was subclinical hypothyroidism (4.1%). In the control group, the prevalence of thyroid disease was 6.6%. The most common was subclinical hypothyroidism (5%). There was a significant difference between diabetics and control subjects p=0.0064. Positive TPOab was found in 8.3% of T2DM patients (N=600) versus 10.3% in the control group (N=282) p=0.412. Positivity for both TPOab and Tgab was found to be 2.5% of T2DM versus 6% of the control subjects p=0.0155.

CONCLUSION: This study suggests that diabetic patients should be screened for asymptomatic thyroid dysfunction.

Institution
National Center of Diabetes, Endocrinology and Genetics, Jordan University of Science and Technology, School of Medicine, Irbid, Jordan.