What is bone resorption?

Bone resorption is a process that involves the breakdown of bone by specialized cells known as osteoclasts. It occurs on a continuous level within the body, with broken bone being replaced by new bone growth. As people age, the rate of resorption tends to exceed the rate of replacement, leading to conditions such as osteoporosis. Also, certain medical conditions, such as hormonal imbalances, can increase bone resorption, which increases susceptibility to fractures.

Osteoclasts work by attaching to individual bone cells and secreting compounds to break down the cells, releasing their mineral content. The minerals enter the bloodstream, where they are processed for recycling to build new bone or eliminated with other bodily waste. Osteoclasts break down bone in response to inflammation, disease, and injury, removing damaged bone to allow it to be replaced by new bone.

In cases where bone resorption is accelerated, the bone breaks down faster than it can be renewed. The bone becomes more porous and brittle, exposing people to the risk of fractures. Depending on the location of the bone resorption, additional problems such as tooth loss may also arise. The rate of resorption can increase with disuse, as seen when people experience fractures and the bone tends to shrink, or in astronauts, who do not work their musculoskeletal systems while in zero gravity and experience losses in bone density as a result.

Applying pressure to a bone can also contribute to bone resorption, as can failing to treat chronic inflammation and bone injury. In healthy individuals, bone can rebuild itself, but in people with untreated chronic conditions, bone can become thinner and more brittle.

There are several ways to assess bone resorption. A blood test may reveal unusually high amounts of minerals in the blood, suggesting a high rate of bone loss. X-rays can reveal bone density loss, as can bone density scans, done specifically to look for density loss. A physical exam can sometimes provide information about bone loss, as seen when dentists check patients with dentures for signs of jaw damage.

If bone resorption is identified, treatment options can be discussed. It is possible to address the underlying cause to stop the rate of bone loss and add supplements to help the patient's body build new bone. In other cases, treatment may focus on supportive care to limit the risks associated with bone density losses.

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