Osteoporosis in Men

Osteoporosis in men is low bone mass with increased fracture risk. Hip and vertebral fractures in men carry higher mortality than in women.

About 1 in 5 men over 50 years will have an osteoporotic fracture. Men are diagnosed less often and treated less often than women. A secondary cause is found in 40 to 60% of men.

Secondary causes are hypogonadism (including androgen deprivation therapy), glucocorticoid use, alcohol excess, smoking, hyperparathyroidism, hypercalciuria, vitamin D deficiency, malabsorption, thyrotoxicosis, myeloma, chronic kidney disease, anticonvulsants, proton pump inhibitors and HIV.

Pathophysiology.

Peak bone mass is higher in men and loss is slower, but sex steroid deficiency (oestradiol as well as testosterone), age related decline in bone formation and secondary causes reduce bone mass and microarchitecture.

Periosteal bone expansion partly offsets loss in older men.

• Often asymptomatic until fracture: vertebral (back pain, height loss, kyphosis), hip, wrist or rib fracture after low trauma.
• Features of the secondary cause: low libido and erectile dysfunction (hypogonadism), Cushingoid features, alcohol excess, kidney stones (hypercalciuria or hyperparathyroidism), anaemia and bone pain (myeloma).

Red flags.

• Severe back pain, height loss over 4 cm or multiple vertebral fractures in a young man.
• Weight loss, anaemia or raised calcium (myeloma, malignancy).

• DXA of lumbar spine and hip (male reference range): osteoporosis is a T-score of -2.5 or lower, or a low trauma hip or vertebral fracture regardless of T-score. Vertebral fracture assessment or lateral spine imaging.
• Fracture risk assessment with a validated tool.
• Secondary cause screen: calcium, phosphate, parathyroid hormone, 25-hydroxyvitamin D, creatinine, alkaline phosphatase, liver tests, thyroid function, full blood count, ESR, serum protein electrophoresis, coeliac serology, morning testosterone with LH and FSH, 24-hour urinary calcium, and prolactin if testosterone is low.

Differential diagnosis.

• Osteomalacia (low phosphate or vitamin D, raised alkaline phosphatase).
• Myeloma and metastatic bone disease.
• Osteogenesis imperfecta and other heritable disorders in young men.

• Treat secondary causes (stop or reduce glucocorticoids, treat hypogonadism and hyperparathyroidism, reduce alcohol and stop smoking).
• Calcium 1000 mg daily from diet and supplements, vitamin D 800 to 2000 units daily to keep 25-hydroxyvitamin D over 50 nmol/L (20 ng/mL), weight bearing and resistance exercise, and falls prevention.
• Treat men with a hip or vertebral fracture, a T-score of -2.5 or lower, or high fracture risk: alendronate 70 mg weekly or risedronate 35 mg weekly (first line). Zoledronic acid 5 mg intravenously yearly (eGFR 35 mL/min or more), or denosumab 60 mg subcutaneously every 6 months. Teriparatide 20 micrograms subcutaneously daily for up to 24 months for very high risk or fractures on treatment.
• Alendronate and risedronate are not used if eGFR is under 35 mL/min or in oesophageal disease. Correct calcium and vitamin D before starting.
• Denosumab must not be stopped abruptly because of rebound vertebral fractures; follow with a bisphosphonate.
• Testosterone in men with confirmed hypogonadism improves bone density but is not a fracture treatment.
• Reassess oral bisphosphonate after 5 years (3 years for zoledronic acid) and continue if fracture risk remains high.

Special groups. Men on androgen deprivation therapy: treat with a bisphosphonate or denosumab 60 mg every 6 months. Chronic kidney disease: select treatment by eGFR.

Monitoring. DXA every 2 years at first, then every 2 to 3 years if stable; calcium, vitamin D and creatinine yearly; adherence at each visit.

Referral and escalation. Endocrinology or metabolic bone service for young men, unexplained causes, fractures on treatment or very high risk.