Evidence for a positive association between serum carnitine and free testosterone levels in uremic men with hemodialysis.

BACKGROUND AND AIMS Low free testosterone levels are associated with sexual dysfunction and an increased risk of cardiovascular disease in male hemodialysis patients. Carnitine deficiency is frequently observed in hemodialysis patients as well. However, the relationship between carnitine and testosterone levels remains unknown. In this study, we examined whether carnitine deficiency was independently associated with low free testosterone levels in male hemodialysis patients. METHODS Nineteen male hemodialysis patients underwent determinations of blood chemistries, including serum levels of free testosterone, carnitine, and pentosidine, one of the well-characterized advanced glycation end products. RESULTS Mean free testosterone levels in hemodialysis patients were significantly lower than those in healthy controls (4.67±2.69 vs. 9.50±3.67 pg/mL, p<0.001). Univariate analysis revealed that carnitine (p=0.023), pentosidine (inversely, p=0.027), blood glucose (inversely, p=0.032), creatinine (p=0.026) levels, and statin use (inversely, p=0.034) were correlated with free testosterone values. Multiple stepwise regression analysis revealed that carnitine (p=0.001) and statin use (inversely, p=0.002) were the independent determinants of age-adjusted free testosterone levels in hemodialysis patients (r² =0.612). CONCLUSIONS The present study gives the first evidence that decreased carnitine levels were independently associated with low free testosterone values in male hemodialysis patients. Our study suggests that decreased carnitine levels may be a novel therapeutic target for uremic men with hemodialysis.