Black women are 30 to 40 percent less likely to sustain a fracture than white women, at every level of bone density, researchers report.

As they note in this week’s Journal of the American Medical Association, previous reports have shown that black women have a lower fracture risk than whites, but it was unclear if bone mineral density (BMD) predicted the risk of fracture to the same degree in each group.

To investigate, Dr. Jane A. Cauley, from the University of Pittsburgh in Pennsylvania, and colleagues analyzed data from 7334 white and 636 black women, between 65 and 94 years of age, who were followed for an average of 6 years.

Fifty-eight black women experienced a total of 61 fractures, compared with 1606 white women who suffered a total of 1712 fractures, the team reports.

In both racial groups, fracture risk increased as BMD fell, but the association was stronger in white women.

After accounting for body weight and other risk factors, a standard drop in BMD raised the risk of fracture by 20 percent in black women and 42 percent and white women.

As noted, within a given BMD range, black women were at least 30 percent less likely to sustain a fracture than their white peers.

Cauley’s team suggests that it “may be appropriate” to develop BMD norms specific to each race, in order to define what constitutes Osteoporosis.

In a related editorial, Dr. Louise S. Acheson, from Case Western Reserve University in Cleveland, Ohio, comments: “If, besides BMD, bone geometry, body composition, bone metabolism, physical capacity, fall risk ... are race-related variables determining fracture risk, measurements related to these factors could be evaluated clinically.”

SOURCE: Journal of the American Medical Association, May 4, 2005.