Trabecular bone pegs fracture risk. (Fast Losers at Increased Risk).

BERLIN--High-resolution two-dimensional and three-dimensional computed tomography images identified a subgroup of perimenopausal women who were losing critical trabecular bone faster than cortical bone.

The finding has important clinical implications because it suggests that an integral measurement of bone mineral density (BMD) may not be powerful enough to identify women most at risk for fractures, Dr. Maximilian Dambacher said at the 10th World Congress on the Menopause.

Dr. Dambacher of Zurich, Switzerland, reported results of a prospective study of 400 perimenopausal women who had sequential Densiscan 1000 images of the internal structures of their bones. The equipment is manufactured by Scanco Medical, Zurich, a company that Dr. Dambacher founded.

Of the women, 34% were "fast bone losers," meaning that they lost more than 3% of trabecular bone per year. (See table.) When all measured sites were considered together, the fast losers lost an average of 7% of trabecular bone per year.

The remaining 66% of the study participants were "slow losers," losing 3% or less of trabecular bone per year. These women lost an average of just 1% of trabecular bone per year.

Loss of cortical bone took place at a much slower rate and was similar between the two groups of women.

"In the 20 months after the beginning of the menopause, you see stable cortical bone and a decrease of trabecular bone. I emphasize that the early postmenopausal bone loss is mainly trabecular," he said at the meeting, sponsored by the International Menopause Society.