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Erectile dysfunction (ED) is defined as the inability to achieve or maintain an erection for satisfactory sexual performance. The prevalence of ED has been estimated as nearly 40% of men >40 years of age1 although these figures are contested.2 ED increases in frequency with age and is estimated to affect 15% of men aged 40–50 years, 45% of men in their 60s and 70% of men older than 70 years.3 Successful erection is a complex system involving reflex action (peripheral nerves and spinal cord), the limbic system (psychogenic stimuli) and the release of nitric oxide. Adequate levels of testosterone are required, and hence an intact hypothalamic/pituitary/testicular axis. Hence, ED can result from disease or treatment that produces hormonal deficiency, neurological impairment, problems with penile blood flow, disorders of tissue mechanics, psychological factors or any combination of these.
Logically, ED secondary to testosterone deficiency should be treated by testosterone replacement. Testosterone levels in men decrease with age.4 Both epidemiological and observational studies have demonstrated that reduced testosterone is associated with increased cardiovascular risk. One meta-analysis showed lower testosterone and higher 17β oestradiol as significant risk predictors despite adjustment for age and body mass index.4 Patients with coronary artery disease (CAD) have been found to have lower testosterone levels than controls, and there is inverse correlation between testosterone and the incidence of major cardiovascular disease (CVD).4 A significant negative correlation has been reported between total testosterone levels and Framingham risk score.4 However, it has been pointed out that ‘It is unclear if this is a causal association or due to low testosterone being a biomarker of poor health’.4 Testosterone replacement as a treatment for …