Osteoporosis is defined as a T-score of:

• A. -2.5 or lower.
• B. -1.0 to -2.5.
• C. Greater than 0.
• D. Exactly -3.0.

Answer: (A)

Bone mineral density is quantified with a T-score, which tells how many standard deviations the patient’s BMD is from the mean of a healthy young adult population. This comparison links bone density directly to fracture risk. An osteoporosis diagnosis is made when the T-score is -2.5 or lower, meaning the bone density is substantially reduced compared with young adults. Between -1.0 and -2.5 is osteopenia, signaling low bone mass but not yet osteoporosis. A T-score greater than -1.0 is considered normal. A value like -3.0 also falls under osteoporosis since it is below the -2.5 threshold, illustrating how the cutoff works for defining the condition.