Prevalence of thyroid dysfunction in patients with Type 2 diabetes mellitus and its correlation with insulin resistance and serum markers for autoimmune thyroiditis

Abstract

Background:The term "THYROID DIABETES" was coined in early literature to depict the influence of thyroid hormone excess in deterioration of glucose control. Although autoimmune thyroid disease is more prevalent in Type1 Diabetes mellitus as a result of their common origin, the prevalence of hypothyroidism and hyperthyroidism is supposed to be similar to that of general population in patient with type2 DM. The purpose of the study was to evaluate the prevalence of thyroid dysfunction in patients with type2 diabetes mellitus and to correlate thyroid abnormalities with insulin resistance and serum markers for autoimmune thyroiditis. Methods: 120 cases of type2 diabetes mellitus patients satisfying WHO criteria without pre-existing thyroid disease were included in the study. Thyroid function test, fasting serum insulin was done.HOMA-IR & HOMA-B (HOMA-Homeostatic model assessment) was calculated. Serum antithyroid peroxidase anibody (anti-TPO) and antithyroglobulin antibodies (anti-TG) and ANA were done. Results: Prevalence of thyroid dysfunction in type2 diabetes mellitus was 28.33% according to our study, which included overt hypothyroidism (15%), subclinical hypothyroidism (8.33%), secondary hypothyroidism (0.83%), overt hyperthyroidism (1.67%) and subclinical hyperthyroidism (2.5%). Anti TPO and anti TG antibodies were elevated in 62.07% cases of hypothyroidism, 40% cases of hyperthyroidism and 6.9% euthyroid cases of type2 DM. Anti TPO and antiTG antibodies were significantly raised in type2DM patient with hypothroidism than that of euthyroid (p value<0.0001).Compared to euthyroid diabetics, hypothyroid cases had lower values of insulin resistance markers like fasting insulin, HOMA-IR and HOMA-B. Hyperthyoid cases had higher values. Conclusion: Hyperthyroid diabetics have higher insulin resistance as fasting insulin, HOMA-IR, HOMA-B showed negative correlation with TSH. (p value<0.05).

Antithyroid Peroxidase and Thyroid Hormones in a Sample of Iraqi Patients with Type 2 Diabetic Mellitus

“…While it was 1.301 ± 0.27 mIU/l and 2.596 ± 0.28 mIU/l in negative and positive groups respectively. Hormones are normally lower when serum TSH is high because of negative feedback which agrees with a previous study [7].…”

Impaired glucose‐stimulated insulin secretion and reduced β‐cell mass in pancreatic islets of hyperthyroid rats

“…The term ‘thyroid diabetes’ was initially coined in 1920 to describe the influence of thyroid hormone excess on deterioration of glucose metabolism (Rohdenburg, ; Sahu et al . ). The reason for the impaired glucose tolerance in hyperthyroidism might be because of increased hepatic glucose production, impaired insulin secretion or peripheral insulin insensitivity (Dimitriadis & Raptis, ).…”

Antithyroid antibody (TPO-Ab) Status in Type 2 Diabetic Patients

“…12 Kahaly found that, in areas of the world where iodine intake is sufficient, autoimmune disorders represent the commonest cause of thyroid dysfunction. 13 Sahu et al (2015) found 28.33% thyroid dysfunction in type 2 diabetic patients. TPO antibody was positive in 62.07% cases of hypothyroidism and 40% cases of hyperthyroidism.…”

“…3 In addition, thyroid dysfunction is another common endocrine disorder that is also increasing day by day 4,5 and may occur in diabetic patients 6,7 especially those with autoimmune thyroid disorder. 8 Thyroid peroxidase (TPO) is an important enzyme that helps in synthesis of thyroid hormones catalyzing the oxidation of iodide on tyrosine residues in thyroglobulin. 9 TPO is a membrane-associated hemo-glycoprotein expressed only in thyrocytes and is one of the most important thyroid gland antigens.…”