Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Figure 7.22 Osteoporosis Osteoporosis is an age-related disorder that causes the gradual loss of bone density and strength. When the thoracic vertebrae are affected, there can be a gradual collapse of the vertebrae. This results in kyphosis, an excessive curvature of the thoracic region. Answer: osteoporosis
Output:
What is the age-related disorder that causes the gradual loss of bone density and strength?