Study of the relation between serum testosterone level and carotid atherosclerosis in elderly men

Objective
The aim of the present study was to evaluate the relationship between serum testosterone concentration and carotid atherosclerosis in elderly men.
Participants and methods
The current study included 40 participants who were classified into two groups; the first group comprised 30 elderly healthy men (the case group) and the second group comprised 10 young males (the control group). Serum level of total testosterone was measured using a commercial immunoassay kit cobas testosterone II; sex hormone binding globulin (SHBG) was measured using a commercial immunoassay kit cobas. SHBG and free androgen index (FAI) were calculated by dividing the total testosterone value by SHBG value and then multiplying it by 100 [total testosterone (nmol/l)/SHBG (nmol/l)Χ100%]. Ultrasonographic measurement of carotid intima-media thickness (IMT) was also carried out.
Results
Total testosterone level was significantly lower in the case group than in the control group ( = 5.354, < 0.001). SHBG was significantly higher in the case group than in the control group ( = 4.796, < 0.001). FAI was significantly lower in the case group than in the control group ( = 4.686, < 0.001). IMT was significantly higher in the case group than in the control group ( = 3.513, = 0.001). As regards the number of plaques, 10 men participants (33.3%) from the case group did not have any plaques, 13 (43.3%) had one plaque, and seven (23.3%) had two plaques; however, in the control group, nine participants (90%) did not have any plaques and only one (10%) had one plaque; therefore, the case group had significantly higher number of plaques than did the control group ( = 3.007, = 0.003). There was a significant negative correlation between total testosterone and SHBG ( = −0.856, < 0.001), a significant positive correlation between total testosterone and FAI ( = 0.957, < 0.001), and a significant negative correlation between testosterone and both IMT ( = −0.501, = 0.005) and number of plaques ( = −0.358, = 0.52). SHBG was negatively correlated with FAI ( = −0.845, < 0.001) but positively correlated with both IMT ( = 0.392, = 0353) and the number of plaques ( = 0.032, = 0.056). There were significant negative correlations between FAI and both IMT ( = −0.601, < 0.001) and the number of plaques ( = −0.461, = 0.010). IMT was positively correlated with the number of plaques ( = 0.760, < 0.001).
Conclusion
These findings suggest that normal physiologic testosterone levels may help to protect men from atherosclerosis. In elderly men, low plasma testosterone is associated with elevated carotid IMT. A negative correlation has been demonstrated between endogenous testosterone levels and IMT of the carotid arteries. These findings suggest that men with lower levels of endogenous testosterone may be at a higher risk for developing atherosclerosis.