A new Canadian multicenter trial has found that vertebral fracture rates are significantly higher in men than in women,¹ and suggests that osteoporosis not only may be under-recognized and undertreated in men until there is progressive deterioration, but that gender bias may play a role in the delay in the diagnosis and management of the disease.

A 12-year observational study of 1588 patients (predominantly women) 50 years of age and older, showed that although the men had significantly higher mean femoral neck and lumbar spine bone mineral density (BMD) measurements at baseline, rates of prior vertebral fracture were twice as high in the men compared with the women (44% vs 22%, P <.001).

Furthermore, the rates of multiple vertebral fractures in the men proved to be more than 3 times those in the women (10% vs 3%, P <.001), reported lead investigator, Anna M. Sawka, MD, of McMaster University in Hamilton, Ontario, Canada.

"I am not surprised by these findings, which indicate that men are more likely to have advanced osteoporosis before it is recognized and treated," John Bilezikian, MD, a professor of medicine and pharmacology at the Columbia University College of Physicians & Surgeons, New York, New York, and an expert on male osteoporosis, told CIAOMed. "The reasons for this are related to perceptions that men 'don't get osteoporosis.' We are therefore not likely to obtain bone densitometry in men nearly as quickly as we are in women. It is the man with the first fragility fracture who gets attention, as demonstrated in this article."

The men who were referred for treatment presented with more severe osteoporosis (reflected in the higher rates of fracture incidence), despite higher areal BMD measurements than those of women. The investigators wrote that, while dual x-ray absorptiometry (DXA) was used for areal measurements, volumetric BMD measurements may have been preferable for the male patients.

Volumetric quantitative computed tomography measures 3-dimensional volumetric BMD and may detect early changes in trabecular, cortical, or integral BMD that extend beyond the technical limits of DXA BMD measurements.²

The elevated lumbar BMD measurements in the male patients may be explained by the presence of osteophytes of degenerative arthritis. Men are known to have a higher prevalence of the osteophytes than women, and this contributes to greater variability of BMD measurements in men.³

Participants in the Canadian trial received 2 years of bisphosphonate therapy "either cyclic etidronate (available in Canada and Europe for osteoporosis treatment, but not approved for this use by the US FDA) or alendronate" for osteoporosis or osteopenia. They had been referred to university-affiliated osteoporosis clinics across Canada and were registered in the Canadian Database for Osteoporosis and Osteopenia Patients (CANDOO), a collaborative, prospective, observational study focusing on the routine clinical care provided by osteoporosis specialists.

Prescription rates for alendronate were similar between the genders; however, the men were much more likely than the women to be prescribed alendronate as first-line therapy for osteoporosis.

Of note, the investigators found that men were much more likely than their female counterparts to have an incident fracture within 2 years of initiating bisphosphonate therapy.

Upward of 25% of the osteoporotic population is male, according to Dr. Bilezikian. Risk factors for osteoporotic fractures in men (ie, smoking; excessive alcohol intake; height loss; previous use of medications such as steroids, thyroid hormone, and antiseizure drugs; family history of osteoporosis) should lead to bone density testing. Compared with the women in the present trial, male participants at study entry had higher body mass index, consumed more alcohol, and had higher rates of smoking and lower levels of exercise.

BMD measurements are known to be predictive of fracture risk, and use of these diagnostic tests for patients with clinical characteristics predisposing to osteoporosis is generally recommended.^4,5 However, the study's authors wrote that, in addition, spinal radiographs should be conducted to investigate the possibility of vertebral fractures in men with back pain, especially in the setting of known secondary causes of osteoporosis, which may include hypogonadism or other predisposing medical conditions as well as the known risk factors.

A limitation of the present study cited by the authors is that they only studied practice patterns in the subspecialty osteoporosis clinic environment and, therefore, it may be difficult to apply these findings to primary care practices or to internal medicine specialists outside the tertiary care setting. Thus, confirmation of the current results in a population-based study may be warranted.

"In the US, many organizations are advocating screening the male population at age 70, which is 5 years after we generally screen the postmenopausal population," Dr. Bilezikian observed. He added that "as we become more aware of the prevalence of osteoporosis in men, we will become more sensitive to the risk factors that should then lead to definitive testing and appropriate therapy."

The CANDOO database used in this study has been sponsored in part by Procter and Gamble.

References

1. Sawka AM, Adachi JD, Papaioannou A, et al. Are there differences between men and women prescribed bisphosphonate therapy in Canadian subspecialty osteoporosis practices? J Rheumatol. 2004;31:1993-1995.

2. Genant HK, Lang T, Fuerst T, et al. Treatment with raloxifene for 2 years increases vertebral bone mineral density as measured by volumetric quantitative computed tomography. Bone. 2004;35:1164-1168.

3. L iu G, Peacock M, Eilam O, Dorulla G, Braunstein E, Johnston CC. Effect of osteoarthritis in the lumbar spine and hip on bone mineral density and diagnosis of osteoporosis in elderly men and women. Osteoporos Int. 1997;7:564-569.

4. K han AA, Brown JP, Kendler DL, et al. The 2002 Canadian bone densitometry recommendations: take-home messages. CMAJ. 2002;167:1141-1145.

5. C ummings SR, Bates D, Black DM. Clinical use of bone densitometry: scientific review. JAMA. 2002;288:1889-1897.