‘Factor-of-risk’ predicts hip fracture in men and women
MedWire News: A biomechanical method for fracture risk assessment, the factor-of risk, is associated with hip fracture risk in men and women, US researchers report.
"Alternative methods of predicting hip fracture are needed since 50% of adults who fracture do not have osteoporosis by bone mineral density (BMD) measurements," remark Alyssa Dufour (Institute for Aging Research, Boston, Massachusetts) and colleagues.
To test whether factor-of-risk, defined as the ratio of applied force on the hip in a fall, to femoral strength, predicts hip fracture, Dufour and team studied 1100 participants (61.4% women) of the population-based Framingham study. All participants had hip BMD, along with weight, height, and age, measurements collected in 1988-1989.
The researchers calculated factor-of-risk by estimating both peak and attenuated force applied to the hip in a sideways fall from standing height, where attenuated force was the peak force adjusted for the cushioning effects of trochanteric soft tissue.
They also estimated femoral strength from femoral neck BMD, using cadaveric femoral strength data.
During a median follow-up period of 11.3 years, 110 (16.3%) women and 26 (6.1%) men suffered a hip fracture.
As reported in the journal Osteoporosis International, factor-of-risk significantly increased the risk for hip fracture after adjustment for age.
More specifically, each standard deviation (SD) increase in peak factor-of-risk was associated with an 88% and 23% increased risk for fracture in men and women, respectively. Similarly, for attenuated factor-of-risk, each SD increase was associated with a respective 78% and 41% increase in fracture risk.
When the researchers examined each factor-of-risk component individually, they found that attenuated force and estimated trochanteric soft tissue thickness both significantly predicted hip fracture in women, even after accounting for the influence of femoral neck BMD.
The same trend of increased risk was observed in the men, but the results were not statistically significant.
Dufour and co-authors note that larger studies using directly measured trochanteric soft tissue thickness are needed to confirm their findings.
However, in future, "the routine measurement of the factor-of-risk might be used to enhance the currently available instruments used to predict fracture risk," they conclude.
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By Laura Dean