If scientists can study millions of genetic differences, could they eventually use our DNA to predict how we will age?
To some extent, genetics can tell us about risk. But it cannot tell us our future.
Some genetic differences are associated with a higher or lower risk of particular diseases. Others have been linked to lifespan, healthspan or exceptional longevity.
But most genetic differences associated with aging have very small effects on their own.
Researchers can therefore combine information from many genetic differences to estimate whether someone has a higher or lower inherited risk for a particular condition or trait.
These combined estimates are often called polygenic risk scores.
The idea is simple: instead of looking at one genetic difference, scientists look at many of them together.
But there are important limitations.
A genetic score is not a prediction of what will definitely happen to an individual. It estimates probability based on patterns observed in populations.
It may also work better in some populations than others because many large genetic studies have historically included people from limited ancestral backgrounds.
Most importantly, our genes are only one influence on aging.
Lifestyle, environment, medical care, disease, biological changes and experiences accumulated over decades all contribute to our health.
This means that two people with similar genetic risks may still age very differently.
As genetic research improves, combining information from many genes may help identify certain risks earlier and contribute to more personalized prevention.
But we are not at the point where a DNA test can reliably tell someone how well they will age, how long they will remain healthy or how long they will live.
