According to the American Society of Plastic Surgeons, during the Twin Days Festival in Twinsburg, Ohio, researchers found pairs of identical twins who had different smoking history. To have a different smoking history, either one twin needs to smoke while the other did not, or one had to have smoked at least five years longer than the other twin, according to the ASPS.

The ASPS said after the photos were taken, they were given to plastic surgeons to analyze the facial features of each twin. The plastic surgeons were not aware of the twins’ smoking history when they looked at the photos. According to ASPS, the goal was for the plastic surgeons to identify “special components of facial aging” that were affected by smoking.

The plastic surgeons found that the scores were lower for the smokers in several areas. The smokers tended to have more sagging of the upper eyelids, and more bags around the lower eyelids and under the eyes, according to ASPS. The smokers also had more facial wrinkles, including more wrinkles around the nose, mouth and lips.