Men with accelerated bone loss have lower estimated bone strength, poorer trabecular microarchitecture, and thinner cortices compared with men without accelerated bone loss, but both groups have similar cortical porosity, according to results from the cross-sectional Osteoporotic Fractures in Men (MrOS) study, published in the Journal of Bone and Mineral Research.
The investigators used high-resolution peripheral quantitative computed tomography scans to measure estimated bone strength and microarchitecture in the distal radius, and in the distal and diaphyseal tibia. A total of 1628 men who had attended the year 14 examination of the MrOS study were evaluated. Researchers retrospectively characterized areal bone mineral density (aBMD) changes from the year 7 to the year 14 examinations based on 3 categories: accelerated BMD loss, defined as >10% decrease in BMD at either the total hip or femoral neck (n=299; 18.4%); expected BMD loss, defined as <10% decrease in BMD (n=1061; 65.2%); and maintained or increased BMD, defined as ≥0% BMD change (n=268; 16.5%).
Approximately 18% of men experienced accelerated bone loss and 16.5% maintained or increased their aBMD between the year 7 and the year 14 examinations. Men with accelerated bone loss were older (mean age, 86 years) compared with men who maintained or experienced expected aBMD loss (mean age, 84 years). Men who experienced accelerated bone loss had lower body weight, height, and body mass index (BMI) at the year 14 examination; moreover, they experienced greater weight loss compared with the year 7 visit and baseline. Men with accelerated bone loss were also less likely to report their health as being excellent or good, drink alcohol, had lower rates of physical activity, and reported more falls in prior years. Nearly half of the men with accelerated bone loss experienced difficulty with ≥1 instrumental activity of daily living, compared with about 30% of the other men.
Total, trabecular, and cortical volumetric BMD in the distal radius were all significantly lower among men with accelerated bone loss (P trend <.001 for all). The cortical area was 5% lower and mean cortical thickness was 11% lower in men who experienced accelerated bone loss compared with men who maintained their aBMD. No difference in cortical porosity was reported across the groups. The microarchitecture of the distal radius showed a 6% lower trabecular number, a 9% greater trabecular separation, and an 11% lower trabecular bone volume fraction in men with accelerated bone loss vs men who maintained or increased their aBMD.
In addition, the total, trabecular, and cortical volumetric BMD in the distal tibia were 12%, 7%, and 6% lower in men with accelerated bones loss compared with men who maintained their aBMD. In the diaphyseal tibia, results also showed lower volumetric BMD, lower cortical area, lower cortical thickness, and lower estimated failure load in men who experienced accelerated bone loss compared with men who maintained their aBMD.
The investigators concluded that the increased impairments reported in men with accelerated bone loss might lead to an increased risk for fracture in this patient population, which warrants further exploration.
Cauley JA, Burghardt AJ, Harrison SL, et al; Osteoporotic Fractures in Men (MrOS). Accelerated bone loss in older men: effects on bone microarchitecture and strength [published online May 11, 2018]. J Bone Miner Res. doi:10.1002/jbmr.3468