MedWire News: Aging women lose more proximal femoral bone strength than aging men, research shows.
The women, on average, lost twice the strength of men in measurements of the single-limb stance (Fstance) and posterolateral fall (Ffall) loading conditions, report Thomas Lang (University of California, San Francisco, USA) and colleagues in the journal Bone.
The analysis included evaluations of age-related proximal femoral density, structure, and strength changes in 111 men and 112 women from Iceland, aged 68 to 87 years old.
The researchers measured longitudinal changes in total femur region quantified by dual X-ray absorptiometry (DXA), areal bone mineral density (aBMD), and trabecular volumetric bone mineral density (tBMD), among other measurements.
Over a 5-year period, men and women both had significant declines in aBMD, tBMD, and in the ratio of cortical to total tissue volume (cvol/ivol).
The men and women also lost bone-loading strength over the 5-year period. On average, the men and women lost proximal femoral whole bone strength at a rate of 4% to 13% every 5 years.
The difference in bone strength loading losses between men and women was statistically significant, with women showing twice the loss of strength compared with men in the Fstance and Ffall loading conditions
The bone strength lost on Ffall was greater than the strength lost on Fstance conditions, with stance strength decreasing at a rate 50% lower than fall strength. The differences in loading strength loss remained statistically significant after adjusting for age and weight.
In a multivariable regression model, the men showed increasing rates of bone strength loss with increasing age.
Women, on the other hand, had greater degrees of bone strength loss with decreasing weight.
"The higher loss of Ffall compared to Fstance supports previous findings in animal and human studies that the sub-volumes of bone stressed under normal physiologic loading are relatively better protected in aging," writes Lang and colleagues.
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