Prevalence of diabetes among hypothyroid subjects

Thyroid dysfunction affects a significant portion of the general population. Most studies have found a higher prevalence of hypothyroidism in women, increasing with age. Prevalence of hyperthyroidism has been found to range 0.5-3.0%. Type 2 diabetes is a major public health problem affecting approximately 4.8 percent of the Bangladeshi population. The study was designed to see the prevalence of type 2 diabetes in hypothyroid patients of any etiology. Four hundred forty two consecutive cases of diagnosed hypothyroidism were recruited in the study. All diagnosed hypothyroid subjects (sub-clinical or overt) reported in one year not known to be diabetic previously, underwent standard OGTT (FPG and 2-hour post 75 gram glucose) before initiation of thyroid hormone replacement. Newly detected diabetes among the subjects diagnosed as hypothyroidism is significantly higher 4.8 vs. 7.01% (p<0.01) and the prevalence of pre-diabetic state Impaired Glucose Tolerance (IGT) is also higher (11% vs. 12.6%) among hypothyroid subjects. Pure IFG (FPG ≥6.1 mmol/l but <7.0 mmol/l, and 2-PG <7.8 mmol/l) was found in 5.2% according to WHO criteria and the prevalence is higher (6.8%) with ADA criteria (considering normal FBG <5.6mmol/l). Diabetes was found in 7.01% among hypothyroid subjects which is higher than the existing known prevalence (4.8%). IGT was also found higher among hypothyroid subjects than population prevalence (8.6%). Further larger sample study is essential to establish the findings.