A medical discovery changed Chris Hemsworth’s life. What is the Alzheimer’s gene, and should you get tested?

“In terms of population wide testing, it’s not really viable or really necessary,” she continues. “If people are concerned because they have family members with Alzheimer’s disease, talk to your GP.”

“[The ApoE4 gene] is a risk factor,” agrees Olivier Piguet, a professor of clinical neuropsychology at The University of Sydney, “but it’s not a genetic mutation that will give you the disease. You have people who have it and will lead a happy life, and you have people who don’t have the gene and will develop the disease.”

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On Limitless, longevity doctor Peter Attia tells Hemsworth that his diagnosis means he is eight to 10 times more likely to develop Alzheimer’s. But this is misleading, says Steiner-Lim. Yes, the risk is eight to 10 times greater compared to those who don’t have the gene, but this is relative.

“The absolute 10-year risks for the [ApoE4 gene that Hemsworth has] for Alzheimer’s disease for age groups 60–69 years, 70–79 years, and 80 years or older are 7 per cent, 16 per cent and 24 per cent for women, and 6 per cent, 12 per cent and 19 per cent for men, respectively. In other words, for Hemsworth, the risk of developing dementia is only 6 in 100 at age 60, rising to a likelihood of 19 in 100 by the time he is 80. ”

What preventative measures can you take?

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While having the ApoE4 gene shouldn’t be cause for panic, it’s still important to understand the ways in which we can reduce our risk of Alzheimer’s. “It’s about ‘how do you mitigate it?’,” says Piguet.

According to global data, 4 in 10 dementia cases may be preventable. So, what can we do to prevent or slow its progression?

“In Australia, physical inactivity and sedentary behaviour contributes almost 18 per cent to the risk of dementia,” says Steiner-Lim.

“Exercise helps cardiovascular health, but also triggers changes in the brain that produce new neurons,” explains Piguet.

Obesity in midlife is also a risk factor, Steiner-Lim says, alongside things like hypertension, depression, smoking and diabetes.

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Cognitive and social inactivity, stress and poor sleep quality, while only emerging risk factors, may also contribute to dementia, particularly later in life.

It’s never too late, and it’s never too early to start mitigating the risk of dementia, says Piguet. “Even if you’re in your 70s and you start exercising it’s a good thing.”

And, he adds, that every little bit counts. “Even a little bit [of a lifestyle change] is good, it’s not like you have to change your whole outlook on life.”

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