Average Loss of Bone Density
The bone tissue is renewed throughout life by a process called “remodeling” that remodeling does not occur simultaneously on all bone surfaces but on tiny homes. In these homes remodeling begins with a phase of bone resorption leading to the formation of a cavity, followed by a phase of bone formation in which the cavity is filled by new bone. This remodeling process is deficient, that is to say that it is formed slightly less bone than it has been absorbed. This balance deficit explains the bone loss associated with age, which will lead to osteoporosis if the bone stock at the end of growth was inadequate or if the activity of remodeling has a record high deficit. The deficit balance is fostered by a deficiency or a lower absorption of calcium and vitamin D. In women, lower rates of female sex hormones at menopause is a factor. This explains that the average loss of bone density becomes significant from 50 years for women and 70 men, with strong individual variations depending on the individual genetic predisposition, diet, physical activity . Osteoporosis is common after prolonged bedrest. It is also a symptom of space sickness.
Often called the “silent epidemic”, osteoporosis poses a greater risk of fractures, the main danger, particularly fractures of the hip, wrist and fractures of the spine.
