Think your looks belie your age? Soon there will be an app to tell you how old you really look, and whether your body's age is out of whack with your chronological age.
"Our study is the first to use 3D facial images to predict biological age in a human population to identify fast and slow agers," says Jing-Dong Han of the Shanghai Institutes of Biological Sciences in China.
The aim, says Han, is to enable family doctors to easily identify patients who are ageing prematurely. If the cause can be identified, such as smoking, overeating or lack of exercise, people can then take action.
Han and his colleagues analysed 3D facial images of 332 Chinese volunteers between the ages of 17 and 77. They identified several features that significantly change with age, such as the slope of the eye, the distance between the mouth and the nose, and the smoothness of skin.
They used this information to create a composite map of the human face as it ages and compared each participant's 3D image with the map. This revealed that on average, facial age differed by about six years either way of real age. The difference between real age and facial age increased after volunteers hit 40.
No need for blood
To check the accuracy of their predictions, the team also took blood samples. Biomarkers in the blood associated with biological ageing – such as levels of cholesterol or a blood protein called albumin – more closely reflected facial age than actual age. For example, someone who looked younger than his or her actual age, also had a cholesterol level expected of a younger person.
The team's "facial age predictor" provides the first non-invasive method for measuring disparities between biological and chronological age. At present, the only alternatives require a blood or tissue sample.
Other teams have demonstrated, for example, that the tips of chromosomes wear down faster in people who are ageing prematurely. Likewise, a chemical change to DNA called methylation, which switches genes on or off, is also more common in ageing tissues.
Han's system, by contrast, requires nothing more than a 3D image. "We will package our predictor into a downloadable app, and doctors will be able to use it provided they can upload a 3D image of their patient into it," says Han. At present, he says 3D cameras are relatively expensive, but is hopeful that the price will fall far enough for them to become commonplace in family clinics.
Stephen Harridge of King's College London, who studies the effect of exercise on ageing, says the latest work doesn't account for all factors that could affect facial appearance and biological fitness. "They used a series of blood markers, such as cholesterol and albumin as markers of health, but these are very basic markers and they can tell us nothing about the amount of physical activity the subjects do, which is likely to be a key measure of health status. This is a particularly interesting point in this study given that the more physically active people are more likely to spend time outside in conditions which might well cause more 'facial ageing' – wear and tear through exposure to the elements".
"It would be very exciting if somebody could develop a universal method that applies to most ethnic groups," says Steve Horvath of the University of California, Los Angeles, who developed the way to estimate biological age from methylation patterns. "The best thing would be a webpage where anybody can upload pictures of themselves to find out their ‘facial age'."
Horvath claims his methylation technique is more accurate, dating biological age to within four years, and applies to all races, ethnic groups and even chimpanzees. But he says he'd love to see whether his age prediction technique correlates with the facial method.
Journal reference: Cell Research, DOI: 10.1038/cr.2015.36
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