Serum testosterone levels and arterial blood pressure in the elderly

The aim of this study was to evaluate the relationship between serum testosterone levels and arterial blood pressure (BP) in the elderly. We studied 356 non-diabetic, non-smoking, non-obese men aged 60 to 80 years and untreated for hypertension. All subjects were evaluated in the morning after an overnight fast. Evaluation included measurements of the following: BP (by mercury sphygmomanometer, Korotkoff I and V), body weight, height and free testosterone (T) plasma levels (by radioimmunoassay). According to the BP values, the subjects were classified as normotensives (NT; n=112; SBP/DBP<140/90 mmHg), systolic and diastolic hypertensives (HT; n=127; SBP/DBP>140/90 mmHg), and isolated systolic hypertensives (ISH; n=117; SBP>140 mmHg and DBP<90 mmHg). T values decreased with increasing age in all 3 groups and was significantly lower in HT (-15%) and ISH men (-21%) than in NT men (p<0.05). In each group, the T levels showed a highly significant negative correlation with BMI (p<0.001). A significant negative correlation was also found between T levels and SBP in NT (r=-0.35, p<0.001), ISH (r=-0.67, p<0.001), and HT (r=-0.19, p<0.05) men, whereas a negative correlation with DBP was observed only in the NT men (r=-0.19, p<0.05). Adjusting for the BMI confirmed a significant difference in plasma T levels between ISH and NT men, but not between HT and NT men. Multiple regression analysis employing BP as a dependent variable confirmed a strong relationship between T levels and SBP in all 3 groups, whereas a significant relationship between T levels and DBP was found only in NT men. In conclusion, although further studies are needed to clarify the relationship between plasma T levels and BP, our findings suggest that in elderly men with ISH, the reduced plasma levels of testosterone might contribute to the increased arterial stiffness typical of these subjects.