People who have elevated homocysteine in their blood, an amino acid that is a known biomarker for cardiovascular disease, may also be at an increased risk of developing age-related macular degeneration ( AMD ).

The study is published in the American Journal of Ophthalmology.

This research was conducted at the Massachusetts Eye and Ear Infirmary and Devers Eye Institute in Portland.

In this largest study of the relationship of this amino acid and age-related macular degeneration, researchers measured the fasting plasma homocystein levels of 934 individuals who were participating in an ancillary study of the Age-Related Eye Disease Study.
Five hundred and forty seven people with age-related macular degeneration and 387 control subjects were tested.

" We found that elevated homocysteine in the blood may be another biomarker for increased risk of age-related macular degeneration," said lead author Johanna M. Seddon, at the Massachusetts Eye and Ear Infirmary. " Homocysteine can be reduced by dietary intake of vitamins B6, B12, and folate, so the relationship between this amino acid and age-related macular degeneration deserves further study."

Researchers found that median values were higher among people with advanced stages of age-related macular degeneration compared to people without AMD, controlling for age and other factors.
Levels considered high in the clinical setting ( above 12 mmol/l ) were also associated with a higher risk of age-related macular degeneration.
The finding adds to the growing body of evidence that there may be overlapping disease mechanisms between age-related macular degeneration and cardiovascular diseases.

Age-related macular degeneration is the leading cause of irreversible visual impairment and blindness among persons aged 60 and older.
With the elderly population steadily growing, the burden related to this loss of visual function will increase.
Limited treatment options exist and prevention remains the best approach for addressing this public health concern.

Seddon and colleagues first proposed this potential relationship between homocysteine and age-related macular degeneration in the mid-1990s and published this hypothesis in a review article in 1999.
She and her team previously established that smoking and nutrition are modifiable factors associated with the development and progression of age-related macular degeneration. They are now also searching for the genes involved in the etiology of this increasing cause of blindness.

Source: Harvard Medical School, 2006


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