Is 60 the New 50? Chronological vs. Biological Aging

CNN posted a very relevant demographic article a couple of days ago comparing biological aging with chronological aging. The focus was on the research of Morgan Levine at Yale Medical School:

Essentially, everyone has two ages: a chronological age, how old the calendar says you are, and a phenotypic or biological age, basically the age at which your body functions as it compares to average fitness or health levels.

People with a biological age lower than their chronological age have a lower mortality risk, while those aging older from a biological standpoint have a higher mortality risk and are potentially more prone to developing the diseases associated with the higher age range. 

But perhaps what's most important here -- unlike results from genetic testing -- is that these are measures that can be changed. Doctors can take this information and empower patients to make changes to lifestyle, diet, exercise and sleep habits, and hopefully take steps to lower the risk and improve their biological age.

This is very important and useful work, since very few of us want to experience a longer life expectancy that involves many more years of disability. Indeed, researchers at the Institute of Health Metrics and Evaluation at the University of Washington have given us Disability-Adjusted Life Years (DALYs) that attempt to take into account the difference between biological and chronological aging (see Chapter 5 of my text for a discussion). The article didn't mention that. 

However, the most important omission in the CNN article was not mentioning that Dr. Levine's work is being done in collaboration with Dr. Eileen Crimmins and her colleagues at the University of Southern California. Earlier this year the two of them published an article in the journal Demography titled "Is 60 the New 50? Examining Changes in Biological Age Over the Past Two Decades." And a clue to how important this is to demographers is the fact that Dr. Crimmins has just been elected President-Elect of the Population Association of America.