Andrology and Sexual Medicine Unit, Department of Clinical Physiopathology, University of Florence, Florence, Italy.
The relationship between metabolic syndrome (MetS), male hypogonadism and their possible interaction in cardiovascular (CV) risk stratification are not completely understood.
We reviewed relationships between testosterone and MetS emphasizing their possible interaction in the pathogenesis of CV diseases.
A systematic search of published evidence was performed using Medline (1969 to January 2011).
Cross-sectional data have shown that subjects with MetS have lower levels of total testosterone (TT; about 3 nmol/L), as hypogonadism is more evident in subjects with erectile dysfunction (ED) than in those without. Longitudinal evidence shows that low T is allocated with a higher risk of subsequent development of MetS, although also the reverse condition is possible. Which are the factors in MetS responsible for the low T is not completely clarified. In clinical studies, increased waist circumference is the major determinants of MetS-associated hypogonadism. Our experiments in rabbits do not support the idea that visceral fat is the main determinant of MetSassociated male hypogonadism. Only few randomized clinical trials have evaluated the impact of testosterone replacement therapy (TRT) in patients with MetS. Available evidence suggests that TRT decreases visceral fat accumulation and ameliorates insulin sensitivity, whereas androgen deprivation increases abdominal adiposity.
The clinical significance of the MetS-associated hypogonadism needs further clarifications. In particular is not completely clarified if low T might be considered a cause or consequence of MetS. The benefit of TRT in term of the reduction of CV risk needs to be confirmed in larger and longer studies.
Corona G, Rastrelli G, Morelli A, Vignozzi L, Mannucci E, Maggi M. Are you the author?
Reference: J Endocrinol Invest. 2011 Jun 27. Epub ahead of print.