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How does osteoporosis increase the risk of fractures?

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Internal structure of a human long bone — bone A long bone of the human body, showing a magnified cross section of the interior.

Osteoporosis increases the risk of fractures by causing a significant reduction in bone mass and a deterioration of the bone's internal microarchitecture.12

In healthy bone, a honeycombed matrix of rigid plates provides structural strength. In individuals with osteoporosis, the balance between bone formation and bone resorption is disrupted, often due to increased resorption by osteoclasts or decreased formation by osteoblasts. As a result, these internal plates become thinner and rodlike, and the spaces between them enlarge.12

This process makes the bone more porous, lighter, and significantly weaker. Consequently, bones become fragile and prone to fracturing from minor traumas or stresses that would typically have no effect on healthy, denser bone. Because there is less bone tissue per unit of volume, the structural integrity of the skeleton is compromised, leading to an increased susceptibility to fractures, particularly in the spine, hips, and wrists.134