Cancellous bone of the spine is greater in black women.

The bone mineral density (BMD) of the spine was measured in the posteroanterior (PA) and lateral projections as well as the total body BMD in 447 black and white women. The lateral projection is comprised predominantly of cancellous bone whereas the total body BMD is predominantly cortical bone, and the PA spine is intermediate in composition. Black women had a higher BMD than white women for each measurement, but the difference was greatest in the lateral spine. Similarly, black women showed less decline in cancellous bone density with aging. The development of a high peak cancellous bone mass with reduced involutional loss may provide a major contribution towards protection against osteoporotic fractures in black women. Metabolic and pharmacologic studies in black and white women should consider the possibility of the influence of a larger cancellous bone mass.