Which of the following best describes a T-score?

• A. A comparison to a young adult reference population
• B. A assessment of bone health over time
• C. A measure of bone mass at a specific age
• D. A calculation of bone strength

Answer: (A)

A T-score specifically represents a comparison of an individual's bone mineral density (BMD) to the average BMD of a healthy young adult population, usually defined as individuals aged 20 to 29. This reference point helps determine if a person has normal bone density, low bone density (osteopenia), or osteoporosis. The T-score provides valuable context by indicating how much one’s bone density deviates from this young adult population, with negative values indicating lower density compared to the reference group.

In contrast, the other options refer to different concepts related to bone health. Assessing bone health over time relates more to long-term monitoring, possibly involving multiple bone density tests, rather than a single T-score measurement. Evaluating bone mass at a specific age pertains to Z-scores, which compare an individual's BMD to age-matched populations, not specifically young adults. Lastly, the concept of bone strength involves factors like architecture and quality of bone that are not directly captured by the T-score, which focuses solely on density. Therefore, option A accurately describes the T-score's function in bone densitometry.