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In modern society, one would be hard-pressed to overestimate
the impact of low back pain (LBP). The costs of this problem, in
both human suffering and dollars, are staggering. Although figures vary
widely, the lifetime prevalence of LBP is usually quoted as ranging
from 60% to 85%, with an annual rate of about
5%. In one recent study, the point prevalence of LBP was
estimated to be 30%.
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LBP is the number one cause of worker absenteeism in the United
States and most other countries in the industrialized world. In
the United Kingdom, it is responsible for 12.5% of all
sick days. A 1985 study estimated that 14% of the entire
population of the United States misses at least 1 workday per year
because of LBP. This figure is highest among people involved in
manual labor, with low job satisfaction and poor workplace social
support. About 2% of workers each year submit claims for
disability from LBP, making it the leading cause of expenditures
for workers’ compensation.
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The chance of someone with LBP returning to work full-time after
any significant absence declines exponentially over time. For example,
after 6 months of disability, the chance of someone with LBP returning
to work full-time is about 50%. After 1 year, this figure
plummets to below 20%. After 2 years of missed work, less
than 3% of disability patients will ever work regular jobs
again. The economic cost of this epidemic is estimated by some experts
to exceed $100 billion per year, not to mention the physical,
emotional, and psychological tolls it exacts.
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Where does all this back pain come from, and who are the people
most at risk? Overall, the ratio between men and women is about
equal, although younger patients with LBP tend to be disproportionately
male, and women report more LBP after the age of 60. For both sexes,
the incidence increases with age. Postacchini and colleagues suggested
that genetics may play a role in certain types of LBP. In patients
with discogenic LBP and those who had undergone surgery for a herniated
disk, 35% and 37%, respectively, had at least
one first-degree relative with a history of discogenic pain, versus
12% in the control group. In these same two groups, 5% and
10% of patients, respectively, also had at least one family
member who had undergone disk surgery, compared to only 1% of
patients without complaints of LBP.
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Many studies have shown an association between LBP and poor general
health. Obesity (and possibly excessive height as well), smoking,
low levels of physical activity, and poor strength and flexibility
all predispose people to LBP. Interestingly, jobs involving heavy
physical labor, and participation in certain sports such as wrestling
and gymnastics, have likewise been associated with back pain. Studies
have also demonstrated an increased number of sick days taken for
other disorders in workers with LBP, and an association between
LBP and chronic illness.
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