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Anaemia
Elevates Risk of Physical Decline in Older People
National
Institutes of Health, July 28, 2003
BETHESDA, MD -- July 28, 2003 -- Anaemia doubles the risk that an older
person will develop serious physical declines that can erode the ability
to live independently, according to a new epidemiological study supported
by the National Institute on Aging (NIA) and others*. It is the first
longitudinal research to find an association between physical decline in
later life and anaemia, a blood condition that affects about 13% of older
Americans.
The study,** published in the August 1, 2003 issue of the American
Journal of Medicine, also found that older people who do not yet have
anaemia, but whose blood tests are just above the traditional cut off
point for diagnosing the condition, are 1.5 times more likely to develop
physical declines than those who have normal blood hemoglobin levels.
"This study suggests that even mild anaemia is a risk factor linked
to reduced ability of older people to function at their fullest
potential," said Jack Guralnik, MD, PhD, an NIA epidemiologist who
co-authored the study. "Further research will tell us whether the
treatment of anaemia can prevent the progressive decline in function that
eventually results in disability."
The investigators, led by Brenda Penninx, PhD, of Wake Forest University
School of Medicine in Winston-Salem, North Carolina, followed a group of
1,146 people, ages 71 and older, for more than 4 years, assessing their
ability to perform three physical tasks: standing balance, a timed 8-foot
walk, and ability to rise from a chair. Each of these activities was
scored on a 5-point scale (0=an inability to do the test; 4=top
performance). These points were added together to create a 0 to 12 overall
score. These scores were correlated with blood samples obtained from the
participants. Anaemia is defined by the World Health Organization (WHO) as
hemoglobin levels below 12g/dL in women and below 13g/dL in men. For this
study, Dr. Penninx classified men and women whose blood hemoglobin levels
were within 1g/dL of the WHO standard (12-13g/dL for women, 13-14g/dL for
men) as having borderline anaemia.
At the end of the four-year study, two-thirds of the participants had at
least modest declines in physical performance scores, with 346 people
(30%) having substantial decreases. Overall, those who did not have
anaemia averaged a 1.4 point decline on the 12-point scale during the
study. In contrast, those who had borderline anaemia dipped an average of
1.8 points and those with anaemia dropped an average of 2.3 points on the
12-point scale.
Women with anaemia showed the greatest physical decline followed by women
who had borderline anaemia. Also, men with anaemia had significantly
greater physical decline than men with normal blood hemoglobin levels. Men
with borderline anaemia were more likely to show physical decline than
those whose hemoglobin levels were slightly higher than the WHO standard.
Excluding people who had ailments associated with anaemia, such as cancer,
kidney disease, and infections, did not change the findings.
In a previous study, using the same data, Dr. Penninx found that a
decrease in physical performance is highly predictive of hospitalization,
nursing home admission and mortality. In his work, Dr. Guralnik has found
that a 1.5 point decrease is associated with a 50% increased risk of
developing a disability that impairs a person's ability to do activities
of daily living, such as bathing, eating and dressing.
"Although no study yet shows that treating anaemia in older people
reduces the incidence of physical decline, our study certainly suggests
that this may be the case," Dr. Penninx said. "Anaemia deserves
clinical attention. That's the take home message."
Anaemia affects at least 3.4 million Americans and is the most common
blood disorder in the United States. It occurs when the body doesn't
produce enough red blood cells or red blood cells are prematurely
destroyed. More specifically, it is defined as a low concentration of
hemoglobin, the main component of red blood cells that transports oxygen
from the lungs to other tissues and then returns carbon dioxide from the
body to the lungs. A person who has anaemia can feel fatigued, dizzy,
apathetic or irritable. Other common symptoms include muscle weakness,
shortness of breath, rapid heart beat, and pale skin. However, the warning
signs are often subtle and can be difficult for doctors to detect.
Anaemia can be caused by vitamin or mineral deficiencies, particularly of
iron, vitamin B12, and folic acid. Underlying diseases including cancer,
rheumatoid arthritis and chronic kidney disease also can trigger anaemia.
But in up to 25% of cases, no cause can be identified. Treatment varies,
but dietary changes, nutritional supplements, and medications can help.
The National Institute on Aging is one of 27 Institutes and Centers that
constitute the National Institutes of Health. The NIA leads Federal
efforts to support and conduct basic, clinical, epidemiological, and
social research on aging and the special needs of older people. Press
releases, fact sheets, and other materials about aging and aging research
can be viewed at the NIA's general information Web site, <http://www.nia.nih.gov>.
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© 2002 Global Action on Aging
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