Final answer:
A T-score of -3 indicates osteoporosis, which is a condition where bones become weak and brittle due to an imbalance between the bone-forming cells, osteoblasts, and the bone-resorbing cells, osteoclasts.
Step-by-step explanation:
The T-score that indicates osteoporosis is A) -3. In bone density tests, a T-score is used to compare an individual's bone density to the average peak bone density of a healthy young adult. Scores are measured in standard deviations (SD) from the average.
A T-score of -1.0 to -2.5 SD indicates osteopenia, which means bone density is lower than normal and may lead to osteoporosis. A T-score of -2.5 SD or lower indicates osteoporosis, meaning that bones are weak and brittle. Therefore, a T-score of -3 would signify that a person has osteoporosis.
Osteoporosis is a condition caused by an imbalance in the activity of two types of bone cells: osteoblasts, which build new bone, and osteoclasts, which break down old bone. When the activity of osteoclasts outpaces that of osteoblasts, bone mass is lost, leading to the development of osteoporosis.