state the main cause of osteoporosis

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Osteoporosis**: Osteoporosis is a bone disease characterized by the thinning of bones, which increases the risk of fractures. Healthy bones have a dense structure, while osteoporotic bones have larger pores, leading to decreased strength.

2. **Identifying the Main Cause**: The primary cause of osteoporosis is bone loss. This condition leads to the weakening of bones, making them more susceptible to fractures.

3. **Role of Estrogen**: The reduction in estrogen levels in the body is a significant factor contributing to osteoporosis. Estrogen is a hormone that plays a crucial role in the formation and maintenance of bone density.

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