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The vision impairment known as age-related macular degeneration
(AMD) may be caused by Chlamydia, a common bacterial infection,
according to a study.
It was found that people with AMD tended to carry higher
levels of antibodies targeted at the bacterium Chlamydia pneumoniae,
which signals a past infection, than those without AMD.
About one-third of Americans over the age of 75 years has
AMD, which occurs when light-sensitive cells in the eye break
down and can make it difficult to read or drive.
Infection with C. pneumoniae normally occurs in the respiratory
system, however may also promote heart disease and chronic
illness. It may also produce inflammation in the blood vessels
that could lead to a heart attack or stroke.
In the study, researchers took blood samples from 43 participants,
25 of whom had AMD.
Patients with AMD were more likely to have higher levels
of anti-C. pneumoniae antibodies than patients without AMD,
even after other factors such as age and smoking were accounted
for.
Researchers suggested that the bacterium might infect eye
tissue or promote inflammation, thereby increasing the risk
of AMD. However, the study participants were mostly male and
had other illnesses, which means the study’s results
may not apply to the population as a whole.
Archives
of Ophthalmology April 2003;121:478-482
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