Testosterone replacement in men with hypogonadism is the most common clinical approach to prevention and treatment of osteoporosis. However this therapy has to be individually balanced against potential risks.
Although testosterone therapy increases BMD in hypogonadal men regardless of age their response to testosterone replacement in terms of change in BMD is variable. It was noticed that previously untreated men with the lowest BMD, particularly those with open epiphyses, benefit the most. Timing of initiation of testosterone replacement in men with hypogonadotrophic hypogonadism seems to be crucial in terms of bone mineral accretion. If androgen replacement is initiated after the age of 20 neither cortical nor trabecular bone reaches normal range. The degree of osteopenia/osteoporosis is in proportion to the delay in initiation of androgen replacement.
Studies in older men with low testosterone showed that only those who had pre- treatment testosterone level of less than 6.9 nmol/L had a significant increase in BMD with testosterone replacement. In eugonadal men some moderate improvement in spine BMD has been achieved with testosterone therap ybut in this particular group extreme caution should be taken regarding potential risks of such therapy.
Bisphosphonates (both alendronate and risedronate) appear to be the treatment of choice for men, primarily for eugonadal men but also for those with hypogonadism when testosterone therapy is contraindicated.
Not only that treatment with alendronate results in significant increase in spine BMD but there is also a significant reduction in vertebral fracture incidence. The response to alendronate does not appear to be dependent on either baseline testosterone or oestradiol concentrations. Even those men who have low serum testosterone seem to benefit to the same extent as those with optimal serum testosterone concentrations.