News Release

Fracture risk lower for black women than white women at all bone mineral density levels

Peer-Reviewed Publication

JAMA Network

Black women have a lower risk of fracture than white women at every level of bone mineral density, according to an article in the May 4 issue of JAMA.

"The recently released U.S. surgeon general's report on bone health and osteoporosis noted that one in two individuals older than 50 years will be at risk for fractures from osteoporosis," according to background information in the article. Despite lower fracture rates among black women, the report stressed that osteoporosis is a risk for any aging man or woman, with low bone mineral density (BMD) being an important predictor for fracture risk. However, it is unknown how BMD is associated with fracture in older black women.

Jane A. Cauley, Dr.P.H., from the University of Pittsburgh, and colleagues examined nonspinal fractures in older women as part of the Study of Osteoporotic Fractures. Data was collected for 1986-1990 from 7,334 white women aged 67-99 years, and for 1996-1998 from 636 black women aged 65-94 years, with an average 6.1 years of follow-up. Bone mineral content (BMC; amount of bone mineral in grams) and bone mineral density (amount in grams of BMC divided by the region of interest in centimeters squared) of the hip and the femoral neck were measured.

Researchers found that black women in the study had a lower risk of fracture than white women at every level of BMD. Fifty-eight black women had a total of 61 fractures, while 1,606 white women had a total of 1,712 fractures. At the beginning of the study, black women had a nine percent higher total hip BMD and a 15 percent higher femoral neck BMD than white women. The association between BMD and fracture was weakened when adjusted for body weight and other risk factors, especially among black women. The absolute incidence of fracture across the pooled BMD distribution was 30 percent to 40 percent lower among black women at every BMD tertile.

"We have demonstrated that reduced BMD of the hip and femoral neck is associated with an increased risk of all nonspinal fractures in older black women in age-adjusted models, a relationship largely mitigated by other risk factors," the researchers write. "Our results suggest that low BMD is useful to identify blacks at risk of experiencing an osteoporotic fracture and those who may benefit from therapy and other preventive measures."

(JAMA. 2005; 293: 2102-2108. Available post-embargo at www.jama.com.)

Editor's Note: This study was supported in part by Public Health Service research grants from the National Institutes of Health. Dr. Cauley has received honoraria from Eli Lilly & Co., Merck & Co., and Novartis and has served on the speaker's bureau for Eli Lilly & Co. and Merck & Co.

Editorial: Should Treatment Thresholds Vary by Race?

In an accompanying editorial, Louise S. Acheson, M.D., M.S., from Case Western Reserve University, Cleveland, discusses the use of race in determining fracture risk.

Dr. Acheson writes: "Middle-aged and older black men and women have higher bone mass and substantially lower fracture rate than whites. Partly because of their reduced risk, blacks have only recently been included in prospective studies of osteoporosis with measurements of bone mineral density (BMD) and fracture incidence."

"An important issue is whether evidence about ethnic differences … indicates a different threshold for treating patients with the same BMD based on differences in skin color, facial features, or self-identified racial groups. This approach is fallible to the extent that race is a nonbiological category, an extremely crude surrogate for biological, environmental, cultural, and behavioral differences among individuals and human populations."

"If, besides BMD, bone geometry, body composition, bone metabolism, physical capacity, fall risk, and eventually genotype are race-related variables determining fracture risk, measurements related to these factors could be evaluated clinically. Research will be needed to test their value. This step will be more appropriate than using race as a variable to determine treatment threshold," Dr. Acheson concludes.

(JAMA. 2005; 293: 2151-2153. Available post-embargo at www.jama.com.)

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