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Adapted from ref. 27 with permission of the publisher.

Adapted from ref. 27 with permission of the publisher.

Fig. 9-2. The T-score regression on age for men by site and device, from the reference databases of the various manufacturers. The expected T-score for an average 65-year-old man ranges from -0.6 at the total femur by DXA to —1.9 at the spine by QCT. Reproduced with permission of the publisher from ref. 27.

Fig. 9-2. The T-score regression on age for men by site and device, from the reference databases of the various manufacturers. The expected T-score for an average 65-year-old man ranges from -0.6 at the total femur by DXA to —1.9 at the spine by QCT. Reproduced with permission of the publisher from ref. 27.

In 2002, ISCD (28) stated that osteoporosis in men should be defined as a T-score of -2.5 or poorer below the young normal mean for men. This is in contrast to the recommendation of the IOF (6) in 2000 in which a T-score of -2.5 based on a female reference database was recommended as the diagnostic criteria for osteoporosis in men. An analysis of data from the European Prospective Osteoporosis Study (EPOS) study (29) suggests that the IOF recommendation may actually be more appropriate when the primary issue is the implication for fracture risk from any given level of bone density. Using BMD and fracture data from 3461 men and women, the EPOS investigators determined that for any given age and spine bone density, the risk of spine fracture was similar in men and women. Incident spine fractures were more common in women than in men simply because, for any given age, bone density in women is lower than in men. Similarly, De Laet et al. (30), using mathematical models and data obtained from the Rotterdam study, suggested that hip fracture risk in men is lower than that in women overall, but appeared to be similar at the same level of femoral neck BMD. They noted that to capture the same proportion of hip fractures in men as in women, the BMD level must be higher than that for women and that the use of gender-specific T-scores would accomplish this. But because absolute risk for fracture is more relevant for intervention decisions, they proposed that the same levels of BMD be used for intervention decisions in men and women. As a consequence, if a given level of bone density in a woman would prompt an intervention to prevent fracture, that same level of bone density should prompt intervention in a man, regardless of the sex-specific T-scores. In an editorial in 2001 in the Journal of Bone and Mineral Research, Melton et al. (31) agreed that the absolute risk of fracture in men and women with the same BMD was similar although they also noted that relatively few men will reach the lowest levels of bone density that are associated with the greatest fracture risks in women. The authors observed that men are generally older than women at any given level of low bone density. Nevertheless, they concluded that it was not yet clear whether a female standard for the diagnosis of osteoporosis or risk assessment could reasonably be applied to men.

As noted earlier, these issues regarding the appropriate use of bone density to diagnosis osteoporosis in men are similar to those for women. Conceptually, the 1991, 1993, and 2000 Consensus Conferences' definitions remain clinically relevant, linking the diagnosis of osteoporosis to an increased risk of fracture. How best to express this quantitatively remains at issue. In some cases however, the T-score reflects more of the variability in bone density at a specific site when measured by a specific technique in a specific population than it reflects fracture risk. As a result, the diagnosis of osteoporosis and the prediction of fracture risk using bone densitometry must currently remain separate processes.

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