We have talked here several times about the possibility of extending the lifespan through several different mechanisms (caloric restriction, pharmacological therapy…), but what if there would be a defined limit for human life expectancy beyond which further extension would not be possible?
A very recent study published in the journal Nature has shown that might be actually the case. Xiao Dong, Brandon Milholland and Jan Vijg used mortality data from more than 40 countries (available at the Human Mortality Database) and concluded that the proportion of people getting to successfully grow old has been increasing since the 1900; probably due to an improvement in health care and health care access. Here I would love to make an aside an make a comment on what that means, especially for those obsesed with the idea that vaccines and medicines are almost as bad as the devil. Were it not for antibiotics, vaccines and other kinds of life saving drugs many of us would not be here. End to the aside.
Back to the study at hand, when they looked at the rates of the socalled supercentenarians (people over 110 years), they found that in the countries where they are more abundant, such as France, Japan, the USA, and the UK, the tendency towards older ages halted after 1995, what’s more, thereafter the oldest people used to die at a lower (0,28years/year) average age than before 1995.
Based on their calculations, the authors of the study think the limit to human life expectancy lies in 115 years (which for me is more than enough time for enjoying life), which is not to say that there are not outliers, there are reports of women living up to 122 years, and that treatments like those introduced at the beginning of our article could extend lifespan further than the genetic and molecular brakes posed by the present epidemiological research.
However, I have to agree with the study authors that the accent should not lie on how long we live -lifespan- but in which condition we do -healthspan-. That is where the research effort should be focused, and that’s what I want to see, a happy healthy 115 year old person.
Evidence for a limit to human lifespan. Dong X, Milholland B, Vijg J. Nature. 2016 Oct 5. doi: 10.1038/nature19793.