Relation of total and free testosterone and sex hormone-binding globulin with cardiovascular risk factors in men aged 24–45 years. The Cardiovascular Risk in Young Finns Study

Background: Total and free testosterone decrease gradually in men with advancing age but it is not completely known how lower levels of testosterone are related with various cardiovascular risk factors. We studied the levels of total testosterone, calculated free testosterone and sex hormone-binding globulin (SHBG), and their relations with cardiovascular risk factors in young Finnish men.

Methods: The study cohort consisted of 24–45-year-old men participating the Cardiovascular Risk in Young Finns Study in the follow-up surveys performed in 2001 (N = 1024) and 2007 (N = 991). Levels of total testosterone, SHBG, lipids, glucose, insulin, blood pressure and anthropometric factors were measured and free testosterone was calculated.

Results: In multivariable analyses adjusted for age, body mass index and life-style factors (alcohol consumption, smoking and physical activity), total and calculated free testosterone were inversely correlated with triglycerides (both P < 0.0001), insulin (P = 0.0004 and P = 0.01), systolic blood pressure (PP = 0.007 and P = 0.01), and directly with high-density lipoprotein (HDL) cholesterol (P < 0.0001 and P = 0.003). SHBG was inversely correlated with triglycerides and insulin, and directly with HDL-cholesterol (all P < 0.001). In longitudinal analyses, lower levels of testosterone and SHBG were associated with higher levels of triglycerides and insulin six years later (all P < 0.01). Baseline level of SHBG was directly associated with HDL-cholesterol (P < 0.0001).

Conclusion: In young and middle-aged men, higher levels of testosterone and SHBG are associated with favourable cardiovascular risk profile characterized by lower levels of triglycerides, insulin and systolic blood pressure, and higher levels of HDL-cholesterol.