It’s long been said that puffing cigarettes speeds up the aging process. Now, new research on identical twins offers mounting evidence that smokers show more signs of premature facial aging, according to findings published in the journal Plastic and Reconstructive Surgery and reported by Medical News Today.

For the study, researchers looked at professional photographs of 79 pairs of identical twins, where one twin smoked regularly and the other had either smoked for only five years or less or did not smoke at all.

Scientists required all participants to submit close-up shots of their faces. In addition, all twins completed and submitted questionnaires about their medical history and lifestyle. Next, researchers reviewed these photos for signs of aging (wrinkles, baggy eyes and skin discoloration) without knowing any details about the participants’ smoking history.

In general, when judges were asked to choose which twin looked older from photographs, in 57 percent of the cases they chose the twin who smoked. If both twins smoked, judges picked out the twin who’d been smoking the longest in 64 percent of cases.

Findings showed that twins who were smokers had significantly more signs of premature aging than those who didn’t. For example, smokers had more sagging of their eyelids and bigger bags under their eyes. They also had more facial wrinkles, especially in their upper and lower lips and lower cheeks. In addition, these smokers had more pronounced lines between their noses and mouths.

According to study authors, “[Smoking] primarily affects the middle and lower thirds of the face…. A five-year difference in smoking history can cause noticeable differences.”

But the twins who smoked showed fewer aging differences in the upper part of their faces, such as eye and forehead lines. Researchers suggested that aging in the face’s upper regions may have more to do with other factors, such as facial muscle activity, while the lower face might be more susceptible to environmental factors.

Smoking also affects cardiovascular risk and steals almost 10 years off your life. Click here for more information.