'Facial Changes Caused by Smoking: A Comparison between Smoking and Nonsmoking Identical Twins' was a study undertaken by the Department of Plastic Surgery at Case Western Reserve University in Ohio to determine how smoking affects the aging process.
The comparison portraits of the identical twins provides shocking visual evidence on how regular cigarette smoking takes a toll on physical appearance. Unsurprisingly, the smoking twin appeared to suffer quicker facial degradation. Although other factors need to be considered in the evaluation, the findings of the study support the longstanding theory that smoking accelerates the aging process.
A Western Reserve University staff member elaborated on the impact of smoking, stating, "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 aging."