Subclinical hypothyroidism and erectile dysfunction: The potential nexus

Purpose: The aim of the study was to evaluate the link between subclinical hypothyroidism (SCH) and erectile dysfunction (ED). Materials and Methods: Seventy-two male patients aged 23-41 years with SCH compared with 25 healthy matched subjects were recruited, and they were divided into Group A: healthy controls (n = 25), Group B: patients with SCH with ED (n = 43), and Group C: patients with SCH without ED (n = 29). Thyroid function test and hormonal assay included total testosterone (TT), sex hormone-binding globulin, free androgen index, and prolactin (PRL) were measured; erectile function was assessed by the 5-item version of the International Index of Erectile Function (IIEF-5) questionnaire. Results: Free triiodothyronine serum level and thyroid uptake were lower in patients with SCH with ED (240.31 +/- 23.85 pg/dL) as compared with patients with SCH without ED or the controls (P = 0.008 and P = 0.004, respectively). Thyroid-stimulating hormone (TSH) serum levels differed significantly; they were normal in the control group (2.86 +/- 1.86 mIU/L), higher in patients with SCH with ED (12.41 +/- 4.73 mIU/L), and relatively low in patients with SCH without ED (7.32 +/- 4.81 mIU/L) (P = 0.001). TT serum level was low in patients with SCH with ED as compared with the controls, but this level was high in patients with SCH without ED as compared with those with SCH with ED (P = 0.001). PRL serum level was high in patients with SCH with or without ED as compared with the controls (P = 0.001). IIEF-5 score was low in patients with SCH with ED (11.73 +/- 5.79) as compared with the controls (P = 0.001, 95% confidence interval [CI] = 14.3985-7.8215) or patients with SCH without ED (P = 0.001, 95% CI = 13.1152-6.7448). Conclusion: SCH-induced ED is related to the elevated PRL and reduced TT and TSH serum levels more than 10 mIU/L. Furthermore, the high TSH serum level was linked with the low IIEF-5 scores; therefore, the severity of SCH is correlated with the severity of ED.