Thyroid activity in obese versus lean male patients with type 2 diabetes

ABSTRACT

Many patients with type 2 diabetes are obese with or without metabolic syndrome. The thyroid activity in those patients is not well studied. The study was performed to evaluate thyroid activity in obese versus lean male patients with type 2 diabetes. the study was conducted on 80 men clinically euthyroid patients with type 2 diabetes, 40 of them were obese [group I]; the other 40 patients were lean [group II]. The control of the study included 40 men healthy subjects, 20 of them were obese [group III] and the other 20 subjects were lean [group IV]. All subjects were males to avoid effects of sex hormones on thyroid function. The study was performed at Al-Azhar University Hospitals on Internal Medicine Department and Diabetic out patient clinic from January to August 2006. Patients as well as control were clinically euthyroid not suffered from other diseases that well known to affect thyroid function. Patients and controls were subjected to history and clinical examinations, measurements of BMI, blood sugar, HbAlc, lipid profile and thyroid function testes including free T3 [FT3], free T4 [FT4] and TSH. serum levels of TSH were significantly higher in type 2 diabetic patients either obese [p<0.01] or not [p<0.01] when compared to controls and in obese vs. lean diabetic patients [p<0.01]. On the other hand serum levels freeT3 and freeT4 were significantly lower in type 2 diabetic patients either obese [p<0.01] or not [p<0.01] when compared to controls and in obese vs. lean diabetic patients [p<0.01]. Serum levels of FT3 was significantly decrease in obese subjects either diabetic or not above 55 years than those below 55 years [p<0.01] for both. Serum levels of HDL-cholesterol were significantly lower, while serum levels of triglycerides were significantly higher in-group I in comparison to groups II and III [p<0.01] for both. On the other hand no significant changes were found in serum levels of total cholesterol and LDL-cholesterol between these groups. BMI correlated positively with triglycerides [r=0.520], with LDL-cholesterol [r=0.620] and with TSH [r=0.510]. BMI Inversely correlated with HDL-cholesterol [r=-0.610], with FT3 [r=-0.620] and with FT4 [r=-0.510], but not correlated with total cholesterol and HbAlc. All mean values of serum TSH, FT3 and FT4 are still within the normal reference range. However, subclinical hypothyroidism [high TSH with normal FT3 and FT4] was found in 12 subjects out of 120 [10%]. Two patients [1.7%] in-group III, 4 patients [3.3%] in-group II and 6 patients [5%] in-group I. type 2 diabetes specially in obese patients are associated with disturbances in thyroid functions within what is considered the normal range, but subclinical hypothyroidism was found in some cases especially if both diabetes and obesity are associated