Relationship between Serum Testosterone Level and Carotid Intima-Media Thickness among Korean Men and Postmenopausal Women

BACKGROUND: Given that the role of serum testosterone on incident cardiovascular disease has been uncertain, it is necessary to find out the relationship between serum testosterone and carotid atherosclerosis. METHODS: The study participants included 1,302 Korean adults (873 men and 429 postmenopausal women) who participated in the Healthy Twin Study and were not receiving androgen deprivation therapy. The participants were classified into three groups: men aged <40 and ≥40 years and postmenopausal women. Total testosterone (TT) and sex hormone-binding globulin (SHBG) concentrations were measured using electrochemiluminescence immunoassays, and free testosterone (cFT) levels were calculated using Vermeulen’s method. Carotid intima-media thickness (IMT) was measured at three levels using a high-resolution B-mode ultrasound equipped with a 7-MHz linear transducer. The associations between sex hormone concentrations and carotid IMT were evaluated using a mixed linear regression analysis. RESULTS: After adjusting for cardiovascular risk factors, TT was found to be inversely associated with common carotid IMT in men aged ≥40 years, with a 4.5% decrease in common carotid IMT for every one-standard deviation increase in TT concentration (P=0.0063). In contrast, TT was not significantly associated with carotid IMT in all segments in men aged <40 years and postmenopausal women. Additionally, SHBG and cFT were not associated with carotid IMT in any segment. CONCLUSION: The significant association between TT level and common carotid IMT in men aged ≥40 years suggests that decreased testosterone levels are involved in the development of atherosclerosis in men.