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Black women have a lower risk of fracture than white women at every
level of bone mineral density according to the JAMA.
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.
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.