Bone mineral density (BMD) reflects what aspect of bone?

Bone mineral density (BMD) primarily measures the concentration of minerals, such as calcium and phosphorus, within the bone tissue. BMD is an important indicator of bone strength and health, as higher mineral density typically correlates with greater structural integrity and a reduced risk of fractures.

BMD is assessed through imaging techniques like dual-energy X-ray absorptiometry (DEXA), which provide insights into the amount of mineral content relative to the volume of bone. This measurement is crucial for diagnosing conditions like osteoporosis, where a reduction in mineral density leads to an increased susceptibility to fractures.

The other aspects mentioned, such as flexibility, growth rate, or age of the bone, do not directly pertain to BMD. Flexibility relates more to the quality of the collagen matrix within the bone, growth rate would indicate how fast bone is forming or remodeling, and age refers to the chronological duration the bone has existed, which might influence BMD but is not a direct reflection of it.