Risk of developing inherited conditions decreases with age, study says

Every year in Australia average life expectancy goes up. We’re living longer, healthier lives thanks to medical advances and information we couldn’t have dreamed of having access to just decades ago.

Early warning screening tests now exist for a wide variety of common conditions including many different types cancer, diabetes and even dementia. They are particularly useful for a person with a family history of certain condition and can give peace of mind to patients concerned about inheriting a faulty gene.

They also give younger generations a better chance at beating these diseases, because early detection is often a matter of life and death.

As we age, we often get sick at a higher rate than when we were younger. You could be forgiven, then, for thinking that our likelihood of developing inherited conditions would also increase with age. But that is not the case. It turns out that the influence of our genes on our risk of disease actually decreases with age.

These findings by researchers from the University of Oxford have been published in the journal PLOS Genetics.

Your genes have a big influence on your likelihood of getting most diseases – from cancer to autoimmune disorders and severe infections. By creating a map of our genes, scientists are now able to make predictions about a person’s future risk of disease and start preventative treatment ahead of time.

Read: Can genetics influence how you respond to the COVID vaccine?

The Oxford research team was investigating whether a person’s risk of developing a particular genetic condition changed as they aged. The study was based on the genomic data of 500,000 people in the UK Biobank, looking at how their genetics affected their risk of developing 24 common diseases.

It was hoped that this information would prove useful as an additional predictive tool for disease.

“Several studies have shown that the prediction power of [genetic tests] varies across age groups in diseases including breast cancer, ischaemic heart disease and prostate cancer,” the study says.

“These results raise the possibility that genetic risk factors may play larger or smaller roles in influencing risk of disease during different age intervals.”

What the researchers found was a steady decrease in the likelihood of developing these conditions as the person aged, meaning a person was more likely to develop any inherited genetic conditions in the first half of their life. If they reached a certain age (depending on the condition) without getting sick, then it was more likely they would never develop the condition.

Read: Here’s what you need to know about MS

“Our work shows that the way in which genetics affects your risk of getting a disease changes throughout life,” lead researcher Professor Gil McVean told ScienceDaily.

“For many diseases, genetic factors are most important in determining whether you will get a disease early in life, while – as you age – other factors come to dominate risk.”

The researchers stressed that although there was a demonstratable drop in the likelihood of genetic conditions as we age, it wasn’t clear why this was the case. They say there may be unknown processes at work, in particular they suspect a person’s environment also interacts with their genes to cause disease or that there are certain phases of life where genetic risks are lesser or greater.

Read: Coronary heart disease is the biggest killer of women worldwide

“We consider a series of possible explanations for the observation and conclude that there must be processes acting that we are currently unaware of, such as distinct phases of life in which genetic risk manifests itself, or interactions between genes and the environment,” the study found.

Have you had screening for genetic conditions in your family? Were there any surprises? How did that affect your plans? Let us know in the comments section below.

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Written by Brad Lockyer