Informally, it’s a measure medical professionals have been using for centuries—if an adult patient looks “old for his age,” that’s generally considered a sign of poor health. A new study published in the British Medical Journal put that folk wisdom to the test, in a study of more than 1,800 twins ages 70 and older. As part of the study, a range of people—including nurses, young men and older women—were asked to assess participants’ age by analyzing photographs of their faces. They found that, twins who were rated as “younger-looking” tended to live longer than their “older-looking” siblings. What’s more, the association between perceived age and longevity persisted even when researchers controlled for physical and mental health, gender and the environment in which participants grew up.
Researchers believe a component of DNA might explain the association between looking younger and living longer. As part of the study, researchers took blood samples from 282 participants, and used these to identify the length of telomeres, or the ends of chromosomes that get shorter each time a cell divides, indicating the decreasing lifespan of that cell. (Incidentally, three American scientists earned a Nobel Prize this year for discovery of telomeres two decades ago and their subsequent research on the DNA component.) The researchers incorporated analysis of telomere length because, as they write:
“Telomere length is an indicator of the number of historic cell replications and the replicative potential of cells. Shorter length is associated with a host of diseases related to aging and lifestyle factors and has been shown to be associated with mortality.”
And, sure enough, they found that “… telomere length, which is currently among the most promising molecular biomarkers of aging, was significantly correlated with perceived age.” That is, generally, the younger study participants looked, the longer their telomeres were.
Apart from DNA indications, researchers found that history of smoking, sun exposure and severe depression were all associated with participants appearing older. These findings, incorporating the impact of both genetic elements and external influences, indicate that the historic practice of sizing up a patient’s age as part of a physical exam continues to have important medical significance. The researchers conclude:
“When assessing health, physicians traditionally compare perceived and chronological age, and for adult patients the expression “looking old for your age” is an indicator of poor health. Our study indicates that this practice, which has existed for decades if not centuries, is actually a useful clinical approach especially given that in a clinical setting perceived age is based on an array of indicators in addition to facial appearance.”