Sex steroids, insulin, and arterial stiffness in women and men

Arterial stiffness may be influenced by sex steroids and insulin; the assoc iation with fasting insulin level may be stronger in women than in men. The refore, we analyzed the effects of sex steroid administration on (1) arteri al stiffness and (2) the relationship between fasting insulin level and art erial stiffness. Twelve male-to-female transsexuals were treated with ethin yl estradiol and cyproterone acetate, and 18 female-to-male transsexuals we re treated with testosterone esters, with assessments made at baseline and after 4 and 12 months. Changes in distensibility and compliance coefficient s (D and CC, respectively) of the common carotid artery, femoral artery (FA ), and brachial artery (BA) were analyzed in relation to changes in fasting plasma levels of glucose, insulin, HDL-cholesterol, and triglycerides. Aft er 4 months of estrogens and antiandrogens in men, significant reductions i n the CC and DC of the FA (P=0.06 and P=0.4, respectively) and BA (P=0.04 a nd P=0.04, respectively) were observed. In women, testosterone, on average, did not affect DC or CC, but the changes in fasting insulin level were str ongly negatively associated with changes in the CC and DC, especially in th e FA and BA. These associations were significantly less strong in genetic m en and were independent of age, mean arterial pressure, and glucose and lip id levels. This experimental study shows (1) that short-term administration of estrogens and antiandrogens increases FA and BA stiffness in men and (2 ) that the fasting insulin level is a stronger determinant of arterial stif fness in women than in men.