Bone mineral density of the ultra-distal radius: are we ignoring valuable information?

Unlabelled: The current study explored the possible utilization in dual-X-ray-absorptiometry scanning (DXA) of the ultra-distal radius (UDR). This region of interest is currently unused and mostly unstudied in this context. The study findings suggest UDR as potential useful region of interest in DXA scanning and warrant further study of the site.

Purpose: Bone mineral density (BMD) measurement of a non-dominant arm is not routinely performed during dual-X-ray-absorptiometry (DXA) test, and the possible utility of ultra-distal (UDR) radius BMD is not well-studied. We evaluated in women, correlations of UDR BMD with fracture prevalence, fracture risk prediction by the fracture risk assessment tool (FRAX), and osteoporosis diagnosed by traditional sites.

Methods: Women who underwent a routine DXA (including their non-dominant forearm and including UDR BMD) in a tertiary medical center were included. Risk factors relevant to FRAX calculation were assessed via a self-administered questionnaire. Spearman correlations of UDR BMD to 10-year risks of major osteoporotic and hip fractures (assessed by FRAX) were explored. The possible added value of UDR BMD in explaining prevalent osteoporotic fractures was assessed using a multivariable regression model incorporating age and traditional osteoporosis diagnosis.

Results: The study included 1245 women with a median age of 66 years (interquartile range: 59-73), of whom 298 (24%) had UDR T-score ≤  - 2.5 and 154 (12%) reported prior fractures. UDR BMD was significantly negatively correlated with FRAX risk score for hip and major osteoporotic fractures (R =  - 0.5 and R =  - 0.41, respectively; P < 0.001). UDR T-score ≤  - 2.5 was associated with higher fracture prevalence (19% vs 10%; P < 0.001) and remained significant after adjusting for traditional BMD and age (OR 1.49, 1.01-2.19; P = 0.043).

Conclusion: UDR BMD correlates both with prior fractures and with predicted fracture risks and might pose added value over traditional DXA sites.