Copyright © 2008 by The Journal of Bone and Joint Surgery, Inc.
Commentary & Perspective
Commentary & Perspective by
Laura Lowe Tosi, MD*,
Children's Hospital Medical Center, Washington, D.C.
Posted February 2008
Our senior population is growing: By 2050, individuals over the
age of sixty-four years will make up more than 20% of the US population1.
Unfortunately, quality of life in the senior years is often diminished by a
fracture, especially a hip fracture. One of every two women and one of every
four men will sustain a low-energy fracture in their lifetime.
As physicians and caregivers, we must seek ways to prevent
as well as treat these injuries, and so the challenge is to identify who is at
risk of sustaining a fracture. To date, most efforts at fracture prevention
have focused on the identification and treatment of osteoporosis. Individuals of
any age who have low bone density are at greater risk of sustaining a fracture
than are their counterparts with normal bone density. Thus, numerous organizations
in the United States and elsewhere have developed guidelines to identify individuals
who are at risk for the development of osteoporosis on the basis of bone
density.
But the picture is not that simple. Approximately half of all
fractures occur in individuals who do not have osteoporosis2. A major challenge to the research community,
therefore, is to identify the full range of risk factors that predict fractures.
As one step in this direction, the World Health Organization
(WHO) plans to release a tool to help physicians assess the long-term risk of
sustaining a fracture. Factors such as patient age, history of fracture, bone
density (when available), body mass index, family history of osteoporosis,
current smoking status, amount of alcohol intake, and steroid use will be
included in the WHO tool and hopefully will provide a more accurate prediction
of an individual's risk of sustaining a fracture within ten years after the
assessment.
Such a tool will have many advantages; nonetheless, it cannot
be considered as the holy grail. As van Helden et al. note in the pages of the
February 2008 issue of JBJS, the WHO ten-year
fracture-risk paradigm has at least two major weaknesses. First, a large
proportion of seniors who sustain a fracture do not, in fact, have
osteoporosis. Second, the algorithm omits at least one major risk factor—a
history or risk of falls. These omissions are particularly unfortunate considering
the recent work by Nguyen et al.3, who reported on the Dubbo
Osteoporosis Epidemiology Study (a prospective population-based cohort study),
and found that postural instability, quadriceps weakness, history of a fall, or
prior fracture are all important predictors of fracture independent of baseline
bone density and age in both men and
women without osteoporosis.
The message is clear: We need to broaden our focus. We can
no longer concentrate solely on bone density as an indicator of fracture risk. At
the same time, we must abandon reliance on arbitrary cutoffs on bone density
level to discriminate between individuals who are at risk for fracture and
those who are not. The relationship between bone density and fracture risk needs
to be seen not in isolation but as part of a comprehensive effort to identify
individuals who are at risk of sustaining a fracture.
It is time to expand the drawing board. Current guidelines and
even the soon-to-be-released WHO ten-year fracture-risk algorithm need to be revisited.
Their focus must be broadened to encompass the prevention of fracture, not just
the identification of osteoporosis. New guidelines must be devised that include
fall history and fall prevention.
This will not be easy: the cause of falls is multifactorial and
the causal factors are difficult to change. Moreover, no one has actually proven
that reducing falls actually reduces fracture rates. Researchers have a big job
ahead.
*The author did not receive any outside funding or grants in support of her research for or preparation of this work. Neither she nor a member of her immediate family received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the author, or a member of her immediate family, is affiliated or associated.
References
1. Day JC. Population projections of the United States by age, sex, race, and Hispanic origin: 1995 to 2050. US Bureau of the Census, Current Population Reports, P25-1130. Washington, DC: US Government Printing Office; 1996.
2. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: report of a WHO study group. Technical Report Series 843. Geneva: World Health Organization; 1994.
3. Nguyen ND, Eisman JA, Center JR, Nguyen TV. Risk factors for fracture in nonosteoporotic men and women. J Clin Endocrinol Metab. 2007;92:955-62.
|
