Are you as old as you look?

This is not to say that by a deeper more meaningful standard you are "only as old as you feel". But is how you look an accurate reflection of your biological age? A group of scientists set out "To determine whether perceived age correlates with survival and important age related phenotypes," and published their findings in the British Journal of Medicine. They conducted their research by comparing photographs of the perceived age of twins with the results of physical tests, cognitive tests and measurements of their leukocyte (white blood cell) telomere length, an objective molecular biomarker of aging (a telomere is a region of DNA at the end of a chromosome that protects it from deterioration). The result was clear cut: "Perceived age—which is widely used by clinicians as a general indication of a patient’s health—is a robust biomarker of ageing that predicts survival among those aged ≥70 and correlates with important functional and molecular ageing phenotypes." I don't think anyone will ask this question, but (obviously) plastic surgery and cosmetic treatments don't count. Slowing down brain aging with sound methods does.