Osteoporosis - Changes of bone remodelling

Osteoporosis is the most prevalent bone problem in the elderly.
This condition presents with decreased bone mass with a normal ratio of mineral to matrix leading to an increase in fractures.
It is four times more common in women than men.

Nowadays the prevalence of osteoporosis is increasing may be due to decreased physical activity & less parity.
Other factors are dietary decrease in calcium, habits like smoking etc.

Changes of bone remodelling in osteoporosis:
Bone is a very active organ, a continuous process called bone remodeling, involves constant resorption - osteoclastic activity and bone formation - osteoblastic activity.
These cells derived from bone marrow progenitors, osteoblasts from mesenchymal stem cells and osteoclasts from hematopoietic white cell lineage.
Cytokines are involved in this in development process regulated by sex steroids.
Aging and loss of estrogen both lead to excessive osteoclastic activity.
A decreased calcium intake and/or decreased absorption lowers the serum ionized calcium level which stimulates parathyroid hormone(pth), it mobilizes calcium from bone by stimulating osteoclastic activity.
Deficiency of estrogen is associated with greater responsiveness of bone to parathyroid hormone.
Pathophysiology
Signs and symptoms
Risk factors and investigations
Investigations
Diagnostic tests and biochemical markers
Hormonal treatment
Estrogen modulators, calcium
Vitamin D
Bisphosphonates
Calcitonin, Fluoride, Tibolone
Prevention