Final answer:
Osteomalacia is the adult condition involving the softening of bones due to demineralization, typically caused by deficiencies in vitamin D, calcium, or phosphate, leading to weakened bones and increased risk of fractures.
Step-by-step explanation:
The adult condition that involves the softening of bones due to demineralization is known as osteomalacia. This condition commonly results from deficiencies in vitamin D, calcium, or phosphate. Osteomalacia can lead to weakened bones that are more prone to fractures and deformities. It is important to distinguish this from other bone disorders such as osteoporosis, which is characterized by a decrease in bone mass and density, making the bones brittle and more likely to fracture. Osteoporosis is associated with the aging process and can result from imbalances between bone resorption and formation, hormonal changes, diseases, and certain medications. While osteoporosis tends to develop silently without outward symptoms until a fracture occurs, osteomalacia might cause bone pain and muscle weakness.
Paget's disease is another condition affecting the skeletal system in adults, but it differs from osteomalacia as it involves a disruption in the normal bone remodeling process. Paget's disease is marked by overactive osteoclasts leading to excessive bone resorption followed by the formation of weak and brittle new bone that is prone to fractures.
Rickets is a similar condition to osteomalacia but occurs in children and is caused by vitamin D deficiency, leading to soft, weak bones and potential skeletal deformities.