Osteoporosis is characterized by all the following except ?
**Core Concept**
Osteoporosis is a systemic skeletal disorder characterized by a decrease in bone mass and density, leading to an increased risk of fractures. It is a multifactorial disease resulting from an imbalance between bone resorption and bone formation.
**Why the Correct Answer is Right**
Osteoporosis is typically associated with an increased bone resorption rate, which can be caused by an overactive osteoclast activity. This process is often mediated by the RANK-RANKL system, where RANKL stimulates the activation of osteoclasts. In contrast, osteoblast activity, which is responsible for bone formation, is decreased in osteoporosis.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because osteoporosis is indeed characterized by an increased bone resorption rate, which is a hallmark of the disease.
* **Option B:** This option is incorrect because osteoporosis is associated with a decrease in bone mass and density, which can lead to an increased risk of fractures.
* **Option C:** This option is incorrect because osteoporosis is indeed characterized by an imbalance between bone resorption and bone formation, with the former being increased and the latter being decreased.
**Clinical Pearl / High-Yield Fact**
The World Health Organization (WHO) defines osteoporosis as a bone mineral density (BMD) T-score of -2.5 or lower, which is a critical threshold for increased fracture risk.
**Correct Answer:** D.