Your risk for several skin conditions could be linked with your eye color, according to a new study.
Research published in the journal Nature Genetics shows that people with blue eyes are at a decreased risk for the autoimmune skin condition vitiligo, when the pigment in skin and hair is lost, resulting in white patches.
The finding suggests that people with brown eyes are then at a decreased risk for the skin cancer melanoma, said researchers from the University of Colorado School of Medicine.
"Genetically, in some ways vitiligo and melanoma are polar opposites. Some of the same genetic variations that make one more likely to have vitiligo make one less likely to have melanoma, and vice-versa," study researcher Dr. Richard Spritz, M.D., of the Human Medical Genetics and Genomics Program at CU, said in a statement.
"Vitiligo is an autoimmune disease, in which a person's immune system attacks their normal pigment cells," Spritz further explained in the statement. "We think that vitiligo represents over-activity of a normal process by which one's immune system searches out and destroys early cancerous melanoma cells."
The study was based on 3,000 people, and looked specifically at 13 genes that are linked with a predisposition to vitiligo. The researchers found that people with vitiligo were significantly less likely to have blue/gray eyes than people without the disease (27 percent with vitiligo, compared with 52 percent of those without).
Meanwhile, 43 percent of those with vitiligo had tan or brown eyes and 30 percent of them had green or hazel eyes, which is a higher percentage than those without vitiligo (27 percent of them had tan or brown eyes and 22 percent of them had green or hazel eyes).
Vitiligo is relatively common -- affecting one in every 100 people in the U.S. -- and is hard to treat, according to the A.D.A.M. Medical Encyclopedia. It can be linked with other autoimmune diseases like hyperthyroidism, Addison's disease and pernicious anemia.
Melanoma, on the other hand, is extremely dangerous and is the No. 1 cause of skin disease-related death. It's more common in people who have lighter skin, blue or green-colored eyes and hair that is red or blond, according to the National Institutes of Health. (Other risk factors include tanning, having at least one really bad, blistering sunburn as a child, spending a lot of time in the sun, living in a sunny region, having a family history of the cancer, or having a lowered immune system.)