Significant Vision Loss from Age-Related Macular
Degeneration Reduced 41% by Vitamin B, Folic Acid
First means of reducing risk of AMD, leading
cause of blindness in senior citizens, other than not smoking
Feb.
24, 2009 – The risk of developing the leading cause of blindness in
older people – age-related macular degeneration (AMD) – was reduced by
34 percent in women taking a combination of vitamins B6 and B12 and
folic acid. The risk of visually significant AMD was 41 percent lower.
There were no men in the study.
Taking a combination of vitamins B6 and B12 and
folic acid appears to decrease the risk of age-related macular
degeneration in women
Age-related macular degeneration (AMD) is a leading
cause of vision loss in older Americans, according to background
information in the article.
Treatment options exist for those with severe cases
of the disease, but the only known prevention method is to avoid
smoking, according to the report in the February 23 issue of Archives
of Internal Medicine, one of the JAMA/Archives journals.
Recent studies have drawn a connection between AMD
and blood levels of homocysteine, an amino acid. High levels of
homocysteine are associated with dysfunction of the blood vessel lining,
whereas treatment with vitamin B6, vitamin B12 and folic acid appears to
reduce homocysteine levels and may reverse this blood vessel
dysfunction.
William G. Christen, Sc.D., of Brigham and Women’s
Hospital and Harvard Medical School, Boston, and colleagues conducted a
randomized, double-blind clinical trial involving 5,442 women age 40 and
older who already had heart disease or at least three risk factors.
About Age-Related Macular Degeneration (AMD)
By National
Eye Institute
Macular
degeneration, or age-related macular degeneration (AMD) is a
leading cause of vision loss in Americans 60 and older. It is a
disease that destroys your sharp, central vision. You need
central vision to see objects clearly and to do tasks such as
reading and driving.
AMD affects the macula, the part
of the eye that allows you to see fine detail. It does not hurt,
but it causes cells in the macula to die. In some cases, AMD
advances so slowly that people notice little change in their
vision. In others, the disease progresses faster and may lead to
a loss of vision in both eyes. Regular comprehensive eye exams
can detect macular degeneration before the disease causes vision
loss. Treatment can slow vision loss. It does not restore
vision.
Of these, 5,205 did not have AMD at the beginning
of the study.
In April 1998, these women were randomly assigned
to take a placebo or a combination of folic acid (2.5 milligrams per
day), pyridoxine hydrochloride (vitamin B6, 50 milligrams per day) and
cyanocobalamin (vitamin B12, 1 milligram per day).
Participants continued the therapy through July
2005 and were tracked for the development of AMD through November 2005.
Over an average of 7.3 years of treatment and
follow-up, 137 new cases of AMD were documented, including 70 cases that
were visually significant (resulting in a visual acuity of 20/30 or
worse).
Of these, 55 AMD cases, 26 visually significant,
occurred in the 2,607 women in the active treatment group, whereas 82 of
the 2,598 women in the placebo group developed AMD, 44 cases of which
were visually significant.
Women taking the supplements had a 34 percent lower
risk of any AMD and a 41 percent lower risk of visually significant AMD.
"The beneficial effect of treatment began to emerge
at approximately two years of follow-up and persisted throughout the
trial," the authors write.
"The trial findings reported herein are the
strongest evidence to date in support of a possible beneficial effect of
folic acid and B vitamin supplements in AMD prevention," the authors
write.
Because they apply to the early stages of disease
development, they appear to represent the first identified way—other
than not smoking—to reduce the risk of AMD in individuals at an average
risk.
"From a public health perspective, this is
particularly important because persons with early AMD are at increased
risk of developing advanced AMD, the leading cause of severe,
irreversible vision loss in older Americans," they add.
Beyond lowering homocysteine levels, potential
mechanisms for the effectiveness of B vitamins and folic acid in
preventing AMD include antioxidant effects and improved function of
blood vessels in the eye, they note.
Editor's Note: This study was supported by grants
from the National Heart, Lung and Blood Institute and from the National
Eye Institute. Vitamin E and its placebo were provided by the Cognis
Corporation. All other agents and their placebos were provided by BASF
corporation.
Related Stories Found in the Health
Section of SeniorJournal.com
Feb.
24, 2009 – The risk of developing the leading cause of blindness in
older people – age-related macular degeneration (AMD) – was reduced by
34 percent in women taking a combination of vitamins B6 and B12 and
folic acid. The risk of visually significant AMD was 41 percent lower.
There were no men in the study. 