Researchers from the Department of Plastic Surgery at Case Western Reserve University in Ohio conducted a study (Facial Changes Caused by Smoking: A Comparison between Smoking and Nonsmoking Identical Twins) that analyzes the physical differences between identical twins, one of whom has smoked cigarettes longer than the other. Focusing primarily on their facial features, researchers collected portraits of 79 sets of twins between the ages of 18 and 78 at the annual Twins Days Festival (from 2007 to 2010) in Twinsburg, Ohio and found that smoking ages the face faster.
The effects of smoking have long been studied and observing the results of identical twins with different habits, in terms of whether they are smokers and for how long, present the direct relationship between smoking and facial degradation. Being that each duo is a physically identical half of the same gene pool, they served as nearly perfect subjects. via My Modern Met
Top photo: The twin on the right smoked 14 years longer than his brother.