Exactly how do they measure the future? How do they know when someone will die?
No, they can tell from your DNA and other tests how old your body is acting, which is biological age.
This is from Fortune magazine, and it appears to describe the men’s study regimen:
https://fortune.com/well/2023/02/09/what-is-my-biological-age/
The study used the Horvath clock measurement to determine biological age. It is based on the information theory of ageing. As cells divide in the body, they have to preserve epigenetic controls on the genes in the cell so that they only produce the proteins they’re supposed to and not erroneous ones that can cause inflammation and promote cancer cell growth.
When cells are very old and are no longer dividing, they are called senescent. These cells can no longer repair DNA damage and can pump out harmful erroneous proteins in mature animals including humans.
The Horvath clock looks at these control points, called DNA methylation sites, in different tissues to see if their methylation pattern matches that of new cells that have just divided. The better the match between old and new, the younger the tissue is, and the younger the biological age of the person.