ORIGINAL ARTICLE Associations of endogenous testosterone and lipid profiles in middle-aged to older Taiwanese men B-P Jiann 1 , J-T Hsieh 2 , S-P Liu 2 , SH-J Hsu 3 and H-C Wu 4 1 Division of Urology, Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; 2 Department of Urology, National Taiwan University Hospital, Taipei, Taiwan; 3 Division of Biochemistry, Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan and 4 Department of Urology, China Medical University Hospital, School of Medicine, China Medical University, Taichung, Taiwan The relationship between endogenous plasma testosterone and plasma lipids was assessed among 856 Taiwanese men ^40 years old originally recruited for an epidemiological study of testosterone deficiency syndrome. Blood samples were drawn from fasting (n ¼ 562) and non-fasting (n ¼ 294) subjects between 0800 to 1100 hours. With adjustment of age, body mass index and sex hormone- binding globulin, the following results were shown: (i) triglyceride (TG) levels were negatively associated with quartile levels of testosterone, and the magnitudes of associations were greater for postprandial TGs than for fasting TGs; (ii) high-density lipoprotein cholesterol (HDL-C) levels were positively related to quartile levels of testosterone, but the associations became insignificant after further control of TGs; and (iii) the calculated low-density lipoprotein cholesterol (LDL-C) levels were positively associated with quartile levels of testosterone. Similar results were obtained in multivariate linear regression analyses with additional control of hypertension and diabetes. In these Taiwanese men, the favorable association of endogenous plasma testosterone with HDL-C counterbalances the unfavorable association of it with LDL-C, while the net influence of testosterone on plasma lipids for cardiovascular system was still in the beneficial direction due to its negative association with postprandial plasma TG levels. International Journal of Impotence Research (2011) 23, 62–69; doi:10.1038/ijir.2011.5; published online 10 March 2011 Keywords: testosterone; postprandial triglycerides; high-density lipoprotein cholesterol; low-density lipoprotein cholesterol Introduction The decrease in the high-density lipoprotein cholesterol (HDL-C) level in boys but not in girls 1 at puberty is related to an increase in the plasma testosterone con- centration. 2 Exogenous androgens induce decrease of serum HDL-C. 3,4 The lifetime risk of developing coro- nary heart disease is higher in men than in women. 5 All these evidences have led to the common belief that testosterone is harmful to the cardiovascular system. However, there was no convincing evidence about the unfavorable relationship of testosterone and coronary heart disease. 3,4 In fact, one cohort 6 and one case–control 7 prospective studies reported sig- nificant correlation between low baseline testoster- one levels and cardiovascular death. The effect of testosterone on plasma lipids may be one of the explanations for the beneficial effect of testosterone on cardiovascular system but it remains poorly defined. Most epidemiological studies demonstrated that endogenous testosterone levels were associated with plasma triglycerides (TGs) and HDL-C in a bene- ficial direction for the cardiovascular system. 3,4,8 But there were some different reports in Japanese men with one study reporting a positive correlation between free testosterone (FT) and TGs; 9 another one, a negative correlation between FT and HDL-C levels; 10 and the other two, no correlation between FT and HDL-C and TGs. 11,12 Studies in this aspect were scanty in other Asian men. Herein, we investigated the relationship of endogenous plasma testosterone and plasma lipids in Taiwanese men who were originally recruited for an epidemiological study of testosterone deficiency syndrome in aging males. Received 22 August 2010; revised 30 December 2010; accepted 31 January 2011; published online 10 March 2011 Correspondence: Dr H-C Wu, Department of Urology, China Medical University Hospital, School of Medicine, China Medical University, Taichung 40447, Taiwan. E-mail: wuhc@mail.cmuh.org.tw International Journal of Impotence Research (2011) 23, 62–69 & 2011 Macmillan Publishers Limited All rights reserved 0955-9930/11 www.nature.com/ijir