Genes, Lifestyle Affect Aging Eyes

April 24, 2007 -- Your genes and lifestyle may affect your odds of developing macular degeneration, a new study shows.

Macular degeneration, also called age-related macular degeneration (AMD), is America's leading cause of vision loss. It becomes more common with age and happens when the macula -- a light-sensitive spot at the back of the eye's retina -- deteriorates, hampering vision.

The new study pinpoints two gene variations that apparently make advanced macular degeneration more likely, especially in overweight smokers.

The researchers' advice: To help prevent macular degeneration, lose extra weight, eat healthfully, don't smoke, and exercise -- no matter what genes you have.

The study by Johanna Seddon, MD, ScM, and colleagues appears in The Journal of the American Medical Association.

Seddon works in Boston at the Ophthalmic Epidemiology and Genetics Service of the Tufts-New England Medical Center.

Macular Degeneration Study

Seddon's team followed 1,466 adults aged 55-80 for about six years, on average.

When the study started, all participants had macular degeneration. Most cases were mild to moderately severe.

During the study, macular degeneration worsened to advanced stages in 281 patients. They were particularly likely to have a certain variation in the CFH and LOC genes.

For instance, the odds of developing advanced macular degeneration were 2.6 times worse for people with two copies of the CFH gene variant and four times higher for people with two copies of the LOC gene variant, compared with people with neither of those gene variants.

The odds were worst for overweight smokers.

Overweight smokers with two copies of the CFH gene variant and two copies of the LOC gene variant were 19 times more likely to develop advanced macular degeneration than lean nonsmokers with no copies of either gene variant.

The mix of genetic and lifestyle factors was key. Eventually, it may be possible to create a risk profile based on patients' genetic and lifestyle factors, Seddon's team notes.