Cardiovascular risk factors

Testosterone plays an ambiguous role in relation to cardiovascular risk factors and its respective role has not been fully resolved (see Chapter 10). The interactions between the CAG repeat polymorphism, serum levels of sex hormones, lifestyle factors and endothelium-dependent and independent vessel relaxation of the brachial artery as well as lipoprotein levels, leptin and insulin concentrations and body composition were described in over 100 eugonadal men of a homogenous population. In agreement with previously demonstrated androgen effects on these parameters it was demonstrated that androgenic effects were attenuated in persons with longer CAG repeats while testosterone levels themselves played only a minor role within the eugonadal range. Significant positive correlations with the length of CAG repeats were seen for endothelial-dependent vasodilatation, HDL-cholesterol concentrations, body fat content, insulin and leptin levels. These results remained stable in multiple regression analyses correcting for age and life-style factors. It was demonstrated by a 5-factor model that adverse and beneficial components are mutually dependent (Zitzmann etal. 2001a; 2003a). Within the investigated range of androgen-related cardiovascular risk factors and eugonadal testosterone levels, the CAG repeat polymorphism could play a more dominant role than testosterone itself. Concerning lipid concentrations, corresponding results are reported in men with X-SBMA (Dejager et al. 2002). Also in agreement, an inclination to develop diabetes mellitus has been described for these patients (Arbizu et al. 1983). Hence, adverse or beneficial effects of a longer or shorter CAG repeat chain in regard to cardiovascular risk will most likely strongly depend on co-factors. The implications in terms of modulation of cardiovascular risk by androgens apply especially to hypogonadal men receiving testosterone substitution. The pharmacogenetic role in this respect of the CAG repeat polymorphism has yet to be elucidated.

Your Heart and Nutrition

Your Heart and Nutrition

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