Twins who smoke show more premature facial aging than their nonsmoking identical twins, and the effects of smoking are most apparent in the lower two-thirds of the face, according to a study in the November issue of Plastic and Reconstructive Surgery®.woman smoking

Bahman Guyuron, MD, professor and chairman, Department of Plastic Surgery, University Hospital Case Medical and Case School of Medicine, in Cleveland and colleagues identified pairs of identical twins who differed by smoking history. In each pair, either one twin smoked and the other did not, or one twin smoked at least 5 years longer. Fifty-seven of the 79 twin pairs studied were women, and the average age was 48.

A professional photographer took standardized, close-up photographs of each twin’s face. The twins also completed questionnaires regarding their medical and lifestyle histories.

Without knowledge of the twins’ smoking history, plastic surgeons analyzed the twins’ facial features, including grading of wrinkles and age-related facial features to identify “specific components of facial aging” that were affected by smoking.

Smokers had more sagging of the upper eyelids, as well as more bags of the lower eyelids and under the eyes. Twins who smoked also had higher scores for facial wrinkles, including more pronounced nasolabial folds, wrinkling of the upper and lower lips and sagging jowls.

Among twins with more than 5 years’ difference in smoking history, the average difference in smoking history was 13 years. Twins with a longer duration of smoking had worse scores for bags on the lower lids and under the eyes and lower lip wrinkles, the study showed. “It is noteworthy that even among sets of twins where both are smokers, a difference in 5 years or more of smoking duration can cause visibly identifiable changes in facial aging,” Guyuron and coauthors write.

Most of the smoking-related differences affected the middle and lower thirds of the face. There were fewer differences in aging of the upper face. In most cases, the examiners were able to identify the smoking or longer-smoking twin based on the differences in facial aging, as rated in photographs.

The twin pairs were similar in other environmental factors that can affect facial aging, including sunscreen use, alcohol intake, and work stress.