Shocking experiment shows major difference in appearance between twins where one smoked and other didn't

A study showed people could easily tell which of two identical twins smoked based on seven key signs of ageing.

It comes after Action on Smoking and Health reports that smoking is the leading cause of preventable death worldwide.

The charity estimates that tobacco causes eight million deaths a year and that 1.2 million are killed from second-hand smoke exposure.

What was the study?

Researchers at the Department of Plastic Surgery at Case Western Reserve University conducted a study which involved comparing photographs of identical twins with different smoking histories.

The purpose was 'to identify the specific components of facial ageing secondary to smoking' within a certain time period.

Between 2007 and 2010, at the Twins Days Festival in Twinsburg, Ohio - the largest annual gathering of twins - researchers studied 79 pairs of twins where only one twin smoked or had smoked for at least five years longer than the other.

Both twins are smokers. The twin on the right smoked 14 years longer than his brother (American Society of Plastic Surgeons)

The twins were asked to fill out questionnaires and had professional photos taken.

A panel of three judges, who didn’t know which twin smoked, then ranked age-related facial features and other signs of ageing on their faces.

What did they find?

The twin on the left is a nonsmoker and the twin on the right smoked for 29 years (American Society of Plastic Surgeons)

Twins who smoked had noticeable facial feature differences compared to their nonsmoking counterparts.

According to the study, the seven main differences were:

• worse scores for upper eyelid skin redundancy
• lower lid bags (puffy areas under the eyes)
• malar bags (swollen pouches under the eyelids onto the cheekbones)
• nasolabial folds (skin creases running from the nose to the corners of the mouth)
• upper lip wrinkles
• lower lip vermillion wrinkles (fine lines or wrinkles that are visible on the red part of the lower lip)
• jowls

"Among twins with greater than five years’ difference in smoking duration, twins who had smoked longer had worse scores for lower lid bags, malar bags, and lower lip vermillion wrinkles," they added.

The twin on the right is a smoker; the twin on the left is a nonsmoker (American Society of Plastic Surgeons)

What did experts say about the findings?

“This study confirms some of what was believed in the most scientific way possible,” said Dr. Bahman Guyuron, who led the research. “With longer follow-up, we believe that every smoking twin might have exhibited a difference in ageing.”

“Smoking reduces the collagen formation, results in collagen degradation and reduces the skin circulation.

“Additionally, nicotine reduces the skin thickness. All of these reduce skin elasticity and [cause] premature ageing.”