Osteoporosis in men: the value of laboratory testing.

UNLABELLED: Evaluation of 234 men referred for osteoporosis found many with undiagnosed secondary causes and multiple unrecognized risk factors.
INTRODUCTION: Studies in women with postmenopausal osteoporosis suggest that many have unrecognized disorders affecting bone. Men are considered more likely to have underlying, possibly correctable causes. We studied the prevalence of risk factors, secondary causes, and laboratory abnormalities in men with and without previously known causes for osteoporosis.
METHODS: We reviewed the charts of 234 men with osteoporosis diagnosed by bone mineral density testing. In addition to screening chemistries, 25-hydroxyvitamin D, testosterone, luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone, and spot urinary calcium-to-creatinine ratio were measured.
RESULTS: The mean age was 70.6 years and mean weight was 76.4 kg. The mean T-score for spine, femoral neck, and forearm was -2.2, -2.4, and -2.3, respectively. Evaluation revealed secondary osteoporosis in 75% overall including hypogonadism, vitamin D deficiency, hypercalciuria, subclinical hyperthyroidism, and hyperparathyroidism. In those men with known secondary osteoporosis at the time of dual energy X-ray absorptiometry testing, additional diagnoses were found in just over half. Vitamin D deficiency and insufficiency were very common, and other common risk factors for osteoporosis included age >65, current smoking, and prior fracture. Half of the subjects had ≥ 4 risk factors.
CONCLUSION: Evaluation revealed a specific cause in about half of men thought to have primary osteoporosis. Among men with known secondary osteoporosis, additional risk factors and secondary causes were frequently identified. In conclusion, a relatively modest evaluation of men with osteoporosis will often provide useful information.