A study published today in the Christmas issue of bmj.com reports that people who look young for their age enjoy a longer life than those who look older than their years.

Frequently, doctors use perceived age as a general indication of a patient’s health. However, there is little research on its validity. In order to find out more, a team of researchers led by Professor Kaare Christensen from the University of Southern Denmark, examined whether perceived age is linked with survival. They investigated important age related traits, such as physical and mental (cognitive) functioning and a molecular biomarker of ageing (leukocyte telomere length).

Telomere length indicates the ability of cells to reproduce. Shorter length is associated with a host of diseases related to ageing, lifestyle factors and death.

A total of 1,826 Danish twins aged 70 years and over underwent physical and cognitive tests in the spring of 2001. Their faces were also photographed.

There were three groups of assessors:
• 20 female geriatric nurses aged 25 to 46
• 10 male student teachers aged 22 to 37
• 11 older women aged 70 to 87

They rated the perceived age of the twins from the facial photographs. The assessors did not know the age range of the twins. In addition, each twin of a pair had their age assessed on different days.

Subsequently, death records were used to track the survival of the twins over a seven year period. Perceived age was significantly associated with survival. This was true even after adjusting for chronological age, sex, and the environment in which each pair of twins grew up. Perceived age, adjusted for chronological age and sex, also correlated with physical and cognitive functioning as well as leukocyte telomere length.

Also, the bigger the difference in perceived age within a twin pair, the more likely it was that the older looking twin died first. The age, sex and professional background of the assessors had no relevance to any of the results.

The authors conclude that perceived age based on facial photographs is a strong biomarker of ageing. It predicts survival among people aged 70 years and over and correlates with important functional and molecular age related characteristics.

To help explain these results, they point to common genetic factors influencing both survival and perceived age.

“Perceived age as a clinically useful biomarker of ageing: cohort study”
Kaare Christensen, professor, Mikael Thinggaard, mathematician, Matt McGue, professor, Helle Rexbye, research fellow, Jacob v B Hjelmborg, associate professor, Abraham Aviv, professor, David Gunn, postdoctoral scientist, Frans van der Ouderaa, vice president corporate research, director of business development, James W Vaupel, professor
BMJ 2009; 339:b5262

Written by Stephanie Brunner (B.A.)