Osteoporosis in men is common and is thus a frequent clinical challenge. Although osteoporosis in men can be of idiopathic origin, in many cases it is found in the presence of one or a combination of risk factors (medical conditions, medications or lifestyle issues)(Ryan et al. Osteoporos Int 2011). A diagnostic work-up is essential in men who present with inappropriately low BMD, particularly in the presence of fractures, and should be designed to identify the presence of any pathophysiological processes that may affect the patient’s prognosis or decisions about therapy.
Most official recommendations are consistent about the initial diagnostic approach (e.g. Watts et al. JCEM 2012). A history and physical exam is useful to ellicit evidence of risk factors for bone loss or fracture, which can then direct focused laboratory evaluations and/or influence therapeutic directions. Basic laboratory measures should be obtained to identify potentially occult problems such as hypercalcemia, renal or hepatic insufficiency, acid-base disturbances, or hematological abnormalities. A measure of vitamin D status (25OHD) is necessary. Other biochemical assessments may be important in selected patients with suggestive clinical presentations but are of uncertain benefit as screening tools (e.g. serum/urine protein electrophoresis, immunological tests for celiac disease, levels of serum parathyroid hormone or TSH, urine calcium excretion). In fact, a recent evaluation of a large group of older men found that many of these tests rarely revealed abnormalities in men with osteoporosis (Fink et al. Osteoporos Int 2016).
Hypogonadism is associated with low bone density and bone loss, and an assessment of serum testosterone levels is routinely recommended in men with osteoporosis. However, in older men serum testosterone levels provide poor predictive value for fracture risk or bone loss. These measures might be most valuable when obtained in men who present with clear clinical evidence of hypogonadism.
In younger men with osteoporosis, a Mendelian disorder may be present. In particular, osteogenesis imperfecta, Ehlers-Danlos and Marfan’s should be considered. These conditions usually present with other phenotypic features that suggest their presence, but genotyping can be useful when the clinical suspicion is high but a diagnosis is not clear.
The diagnosis of idiopathic osteoporosis should be considered in the absence of any secondary causes of osteoporosis or a genetic syndrome associated with osteoporosis.