The incidence of testosterone deficiency in men with long-term spinal cord injury

BackgroundThe testosterone deficiency syndrome (TDS) is increasingly recognized as a distinct entity, especially in aging men, and is characterized by typical clinical and biochemical effects. These include sexual dysfunction, mood alterations, loss of lean muscle, skin changes, osteoporosis, and changes in visceral fat. The same clinical features occur in men with a spinal cord injury (SCI). This study was carried out to determine the incidence of testosterone deficiency in men with a long standing SCI and to examine the possible need for testosterone replacement therapy for such men.MethodsForty-two long-term SCI men with an average age of 54 years and average time of 20 years since injury were studied. Their serum total testosterone (TT) and serum sex hormone binding globulin (SHBG) levels were measured and free testosterone levels were calculated.ResultsThe serum TT levels were all well above the recommended normal lower limit of 12 nmol/l. The average serum TT level was 17.4 nmol/l. The serum SHBG levels were above the lower limit of normal of 13 nmol/l and below the upper limit of normal of 70 nmol/l. The average SHBG level was 37.5 nmol/l, which is well within normal limits. The calculated free testosterone levels were all well above the recommended lower limit of normal of 225 pmol/l. The average free testosterone level was well above this level at 348 pmol/l. All these levels were within the current internationally recommended normal range.ConclusionsIn this group of 42 men with long-term SCI the serum TT, SHBG, and free testosterone levels were normal. However, there are still large gaps in available information and further studies are recommended.