Reports of studies on bone health have often spoken about how the loss in "quantity and mass" of the bones in an elderly population is the primary cause for frequent fractures and general bone health deterioration.
However, studies conducted by scientists at the Lawrence Berkeley National Laboratory (U.S Department of Energy) now add to that line of thought. Apparently, the loss of bone health also occurs due to a qualitative change for the worse inside the bones of the elderly.
This looks at bone health of the aging population from an intrinsic perspective. The study was supported by a grant from the National Institutes of Health. (1)
With the help of techniques such as X-rays, macroscopic fracture testing tools and electron-based analytical devices, the researchers examined the cortical bones of the senior population and were able to view and assess the qualitative degradation of the mechanical properties of their bones.
The reason cortical bones were studied is because they form the solid mass of bone and account for almost 80 percent of the body’s total skeletal weight and are responsible for body movement and protection of our internal organs. (2)
The cortical bones also give us primary shape, toughness and strength apart from stiffness, all of which are possible because of the nanoscale structure of the cortical bones.
The study looked at multiple length scale as well as hierarchical structure of these bones. The lengths of scale that were studied in the research ranged from the molecular level up to the osteonal structures at millimetre levels.
According to Berkeley Lab materials scientist Robert Ritchie, “Based on multi-scale structural and mechanical tests, we attribute this degradation to a hierarchical series of coupled mechanisms that start at the molecular level.” (3)
To assess if the bone health of a person is taking a turn for the good, observations of cortical bones at small length scales need to be made. A positive development would signal a better intrinsic strengthening mechanism. The extrinsic toughness mechanisms would be occurring at longer scales inhibiting the growth of cracks.