Thyroid Dysfunction and Insulin Resistance

Background: Insulin resistance is a state in which a given concentration of insulin produces biological effect less than expected. The syndrome of insulin resistance involves a broad clinical spectrum, which includes obesity, glucose intolerance, diabetes, and metabolic syndrome. Many of these disorders are associated with various endocrine, metabolic, and genetic conditions. They may also be associated with some immunological diseases and may exhibit distinct phenotypic characteristics.

Aim of the Work: This study aimed to determine the association between altered thyroid hormones and insulin resistance.

Patients and Methods: This study was conducted at Fayoum University Hospital in the period from February to June 2015. It included 90 age and sex-matched non diabetic individuals; they were divided to 3 groups; 30 patients with uncontrolled hypothyroidism, 30 patients with uncontrolled hyperthyroidism according to their thyroid stimulating hormone levels (TSH) and 30 healthy volunteers as a control group. Thyroid stimulating hormone level (TSH) was measured for the control group. For the 3 groups, fasting plasma glucose (FPG) and fasting plasma insulin concentration (FPI) were done. Homeostatic model assessment of insulin resistance was calculated using the formula: HOMA-IR= (FPI× FPG/22.5).

Results: It was found that 50% of hypothyroid patients, 36% of hyperthyroid patients and only 16.5% of the control group had insulin resistance (IR), and the difference was statically significant (p=0.024).

Conclusion: It was found that 50% of hypothyroid and 36% of hyperthyroid had insulin resistance and only 17% of the control group had insulin resistance and this was not correlated to either body weight, BMI, as well as waist circumference.