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Research Christmas 2009: Young and Old

Perceived age as clinically useful biomarker of ageing: cohort study

BMJ 2009; 339 doi: (Published 14 December 2009) Cite this as: BMJ 2009;339:b5262
  1. Kaare Christensen, professor1,
  2. Mikael Thinggaard, mathematician1,
  3. Matt McGue, professor12,
  4. Helle Rexbye, research fellow1,
  5. Jacob v B Hjelmborg, associate professor1,
  6. Abraham Aviv, professor3,
  7. David Gunn, postdoctoral scientist4,
  8. Frans van der Ouderaa, vice president corporate research 4, director of business development6,
  9. James W Vaupel, professor5
  1. 1Danish Twin Registry and Danish Aging Research Center, Institute of Public Health, University of Southern Denmark, DK-5000 Odense C, Denmark
  2. 2Department of Psychology, University of Minnesota, Minneapolis, MN, USA
  3. 3Center of Human Development and Aging, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ, USA
  4. 4Unilever Discover, Colworth House, Sharnbrook, Bedfordshire
  5. 5Max Planck Institute for Demographic Research, Rostock, Germany
  6. 6Netherlands Consortium for Healthy Ageing, Leiden University Medical Centre Leiden, LUMC, 2300RC Leiden, Netherlands
  1. Correspondence to: K Christensen kchristensen{at}
  • Accepted 15 November 2009


Objective To determine whether perceived age correlates with survival and important age related phenotypes.

Design Follow-up study, with survival of twins determined up to January 2008, by which time 675 (37%) had died.

Setting Population based twin cohort in Denmark.

Participants 20 nurses, 10 young men, and 11 older women (assessors); 1826 twins aged ≥70.

Main outcome measures Assessors: perceived age of twins from photographs. Twins: physical and cognitive tests and molecular biomarker of ageing (leucocyte telomere length).

Results For all three groups of assessors, perceived age was significantly associated with survival, even after adjustment for chronological age, sex, and rearing environment. Perceived age was still significantly associated with survival after further adjustment for physical and cognitive functioning. The likelihood that the older looking twin of the pair died first increased with increasing discordance in perceived age within the twin pair—that is, the bigger the difference in perceived age within the pair, the more likely that the older looking twin died first. Twin analyses suggested that common genetic factors influence both perceived age and survival. Perceived age, controlled for chronological age and sex, also correlated significantly with physical and cognitive functioning as well as with leucocyte telomere length.

Conclusion 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.


  • We thank Unilever for supplying the composite images, which were generated by Sharon Catt with software from the Perception Laboratory, University of St Andrews.

  • Contributors: KC and JWV initiated the study, obtained funding, supervised the analyses, and KC was mainly responsible for writing the report and is guarantor. HR, AA, DG, and FvdO helped to develop the protocol, assisted in the analysis of the results, and helped to write the report. MT, MM, and JH assisted in the protocol design and the data analyses, and helped to write the report.

  • Funding: This study was funded by Unilever. The Longitudinal Study of Aging Danish Twins (LSADT) received grants from the US National Institutes of Health (grant No NIA P01 AG008761). The Danish Aging Research Center is supported by a grant from the VELUX foundation. No funders had any role in the study design, analysis, or writing of this paper.

  • Competing interests: None declared.

  • Ethical approval: The study was approved by the regional scientific ethical committee in Denmark (Case No VF20040241).

  • Data sharing: No additional data available.

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