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

Abstract

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. 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. The study included 1245 women with a median age of 66years (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). UDR BMD correlates both with prior fractures and with predicted fracture risks and might pose added value over traditional DXA sites.