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World J Diabetes. Dec 15, 2014; 5(6): 901-904
Published online Dec 15, 2014. doi: 10.4239/wjd.v5.i6.901
Diabetes mellitus and hypothyroidism: Strange bedfellows or mutual companions?
Barry I Joffe, Larry A Distiller
Barry I Joffe, Larry A Distiller, Centre for Diabetes and Endocrinology, Johannesburg, Gauteng 2198, South Africa
Author contributions: Joffe BI and Distiller LA contributed equally to this work.
Correspondence to: Barry I Joffe, DSc, FCP (SA), FRCP (London), Professor, Emeritus Professor and Physician, Centre for Diabetes and Endocrinology, PO Box 2900, Saxonwold, Johannesburg, Gauteng 2198, South Africa. barry@cdecentre.co.za
Telephone: +27-11-7126000 Fax: +27-11-7286661
Received: July 6, 2014
Revised: October 14, 2014
Accepted: October 23, 2014
Published online: December 15, 2014
Processing time: 159 Days and 21.8 Hours
Abstract

Clinicians should be cognizant of the close relationship that exists between two of the most common endocrine disorders, primary hypothyroidism and diabetes mellitus. This applies to patients with both type 1 and type 2 diabetes mellitus (T1DM and T2DM respectively). However, the association is greater in T1DM, probably because of the shared autoimmune predisposition. In patients with T2DM, the relationship is somewhat weaker and the explanation less clear-cut. Factors such as dietary iodine deficiency, metformin-induced thyroid stimulating hormone suppression and poor glycemic control may all be implicated. Further translational research is required for greater clarification. Biochemical screening for abnormal thyroid function in individuals who have diabetes is warranted, particularly in females with T1DM, and therapy with L-thyroxine appropriately instituted if hypothyroidism is confirmed.

Keywords: Type 1 diabetes; Type 2 diabetes; Primary hypothyroidism; Autoimmune disorders; Thyroid screening; Thyroid treatment

Core tip: Clinicians should be cognisant of the close relationship that exists between two of the commonest endocrine disorders, primary hypothyroidism and diabetes mellitus. This applies to both type 1 and type 2 diabetes. However the association is greater in type 1 diabetes, probably due to shared autoimmune predisposition. In type 2 diabetes, the connection is more complex. Biochemical screening for thyroid dysfunction in patients with diabetes is advised.