Smoking and skin aging in identical twins.

BACKGROUND A twin pair can provide a rare opportunity to control for genetic susceptibility and exposure variables, which often serve as major confounders in population-based studies on the relationship between smoking and skin aging. OBSERVATIONS We describe a unique twin pair who spent not only their first 2 decades of life together but also in their later decades had the same type of job at the same latitude, resulting in well-matched levels of significant sun exposure. However, the twins differed markedly in regard to smoking history; the twin with an approximately 52.5-pack-year smoking history showed more severe skin aging than did the nonsmoking twin. CONCLUSION The difference in skin aging illustrated by this twin pair may serve as a motivator for smoking cessation.