Objective: The number of studies that investigate thyroid functions in obese patients is limited, and little known about the effect of co-existence of type 2 diabetes mellitus on thyroid functions. In our study, we aimed to evaluate the spectrum of thyroid function in the both diabetic and non-diabetic obese patients.
Materials-Methods: 145 obese patients who were admitted to our department of endocrinology and metabolism, between June 2014 and December 2015, have been included in the study. The patients have been grouped according to their BMI values and co-existence of type 2 diabetes mellitus. Clinical and laboratory data of the patients were analyzed retrospectively and cross-sectionally. Statistical analyses were performed by using frequency analysis, T-test, Chi-square test and Pearson correlation tests.
Results: Primary hypothyroidism, subclinical hypothyroidism and subclinical hyperthyroidism were determined in 1.4, 0.7 and 2.8% of the patients respectively. Isolated elevation of free T3 and free T4 levels were determined in 26.6% and 1.4% of the patients respectively. No statistically significant difference was found between diabetic and non-diabetic groups for these parameters.
There were statistically significant positive correlations between BMI and free T4 levels, and also free T3 levels (P=0.001, P=0.002, respectively). There was no significant correlation between BMI and TSH (P=0.717). There was no significant correlation between age and BMI values (P=0.237).
There were no statistically significant difference for BMI, TSH (thyroid stimulating hormone) and anti-TPO (anti-thyroid peroxidase) values between diabetic (n=69) and non-diabetic obese patients (n=76) (P=0.623, P=0.937, P=0.114 respectively).
Conclusion: Our results suggest that obesity may be associated with elevated free T4 and free T3 levels. Coexistence of type 2 diabetes mellitus seems to have no effect on thyroid functions.