A study on prevalence of thyroid auto-immunity in type 1 diabetes mellitus.

Type 1 diabetes mellitus is an auto-immune disease. It is associated with other auto-immune endocrine disorders and auto-immune impairment of non-endocrine tissue. Auto-immune thyroid disease is one of the most frequent auto-immune diseases associated with it. Hypothyroidism can decrease insulin requirement in such patients and hyperthyroidism may cause glucose intolerance. This study attempts to review this concept and detect overt and subclinical forms of auto-immune thyroid disease in type 1 diabetics and to find its correlation with age, sex and duration of diabetes. Fifty type 1 diabetes mellitus patients were selected from SSG Hospital, Vadodara between April 2007 and September 2008. After detailed history and examination, haemogram, urine analysis, fasting and 2-hour postprandial blood glucose level, serum free T4, TSH and antithyroid peroxidase antibody level were performed. The prevalence of auto-immune thyroid disease in type 1 diabetics was 60% with 40% having thyroid disorders (24% overt hypothyroidism, 8% subclinical hypothyroidism and 8% hyperthyroidism). Patients who were females (70% versus 53% in males), older (53.3% in 15-20 years age group versus 71% in 25-30 years age group), had a longer duration of diabetes (25% in those with the disease for <2 years and 100% in those >6 years) were more likely to have auto-immune thyroid disease than their counterparts. Thyroid auto-immunity is frequently associated with type 1 diabetes mellitus and patients should undergo antibody screening to detect the same and to find out assosiated undiagnosed thyroid dysfunction.