Genetics play part in premature graying

Why do some people go gray at a young age?

Hair goes gray as cells called melanocytes at the base of each hair follicle get damaged by disease, environmental exposures or simply age.

Everyone has some gray hairs throughout life, but the balance tends to tip in the 40s or 50s, with the rate of change varying by genetics, gender and ethnicity, said Dr. James Kirkland, director of the Robert and Arlene Kogod Center on Aging at the Mayo Clinic.

Blacks tend to go gray later than whites, with Asians falling somewhere in between. Women generally gray later than men. The age you go gray is determined primarily by genetics, so if one or both parents went gray at an early age, you are more likely to go gray at a younger age as well.

Smoking can also accelerate color change, and early graying could be a sign of autoimmune, thyroid or heart disease.

‘‘If you’ve got heart disease and your hair is gray, it’s a sign of worse heart disease,’’ Kirkland said.

Some people held in concentration camps during World War II who were deprived of proper nutrition also went prematurely gray, said Dr. Wilma Bergfeld, a dermatologist at the Cleveland Clinic who specializes in hair disorders. ‘‘Everything is determined by the health of the pigmentproducing cell,’’ she said.

Bergfeld said she does not know of anyone who has gone gray because of weight loss or exercise. Most activities that are damaging to the hair, like rapidly losing more than 20 pounds or getting chemotherapy treatment, will cause hair loss rather than a change of color, she said.

There are no drugs approved to restore hair color, though in early testing of the anti-hairloss drug minoxidil, researchers noticed the medication sometimes also restored hair color.

It is not clear whether chronic stress turns hair gray. Although President Barack Obama’s hair turned gray during his time in office, studies that have looked at stress and hair color have been inconclusive, Kirkland said. (He also aged from 47 to 55, a time when many people’s hair turns gray.)

‘‘The consensus is that stress possibly does it,’’ he said. ‘‘But that’s a gut feeling rather than convincing evidence.’’