Why do some people stay healthy into their 80s or 90s, while others develop health problems much earlier?
The genes we inherit are part of the answer. But there is no single gene that decides how we will age.
We all inherit small differences in our DNA. Some may slightly increase the chance of developing certain diseases. Others may influence how well our bodies maintain and protect themselves over time.
On their own, most of these genetic differences have only a very small effect.
What matters is the combination of many of them.
Scientists call this polygenic, meaning that many genes-not just one-contribute to a particular characteristic.
Large genetic studies are now helping researchers understand how these small differences may influence some of the processes involved in aging.
For example, our genes can affect how our bodies handle cholesterol and fats, control inflammation, regulate metabolism and repair damaged DNA.
But genes are only part of what determines our health as we grow older.
How we age is also influenced by our lifestyle, environment, medical conditions and the many exposures we experience throughout life.
This is why having genes associated with a higher risk does not mean that a person will necessarily develop a disease. And having favorable genetic characteristics does not guarantee a long and healthy life.
Modern genetics is therefore moving away from the idea of finding one “longevity gene.” Instead, scientists are asking a much more useful question:
How do many small genetic differences work together to influence our health as we age?
Understanding these differences may eventually help us identify individual health risks earlier and improve prevention.
