In this largest study of the relationship of this amino acid and AMD, 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 AMD and 387 control subjects were tested.
"We found that elevated homocysteine in the blood may be another biomarker for increased risk of AMD," said lead author Johanna M. Seddon, MD, director of epidemiology at the Massachusetts Eye and Ear Infirmary. Seddon is also an associate professor of ophthalmology at Harvard Medical School. "Homocysteine can be reduced by dietary intake of vitamins B6, B12, and folate, so the relationship between this amino acid and AMD deserves further study."
Researchers found that median values were higher among people with advanced stages of AMD 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 AMD. Seddon's finding adds to the growing body of evidence that there may be overlapping disease mechanisms between AMD 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.