After two decades of acting, Chris Hemsworth revealed he will take a break from his career, after learning he has a much higher-than-average chance of developing Alzheimer's disease.
The Australian actor learned the news while he was filming a new National Geographic docuseries for Disney+, Limitless, which explores the impacts of time and age.
Throughout the series, Hemsworth undergoes multiple genetic tests to see what his future might have waiting for him.
He is confronted by his own mortality in episode five.
Hemsworth eight to 10 times more likely to develop Alzheimer’s
The Marvel actor was filmed as his doctor informed him he was eight to 10 times more likely to develop the disease.
"His makeup includes two copies of the gene ApoE4, one from his mother," said Peter Attia, the longevity doctor in the docuseries. The other he inherited from his father.
More on that below.
In a recent interview with Vanity Fair, Hemsworth emphasised that it’s not a hard diagnosis of Alzheimer’s.
However, he told the tabloid magazine that the double occurrence of the gene places him in a category of much higher risk of being impacted by the condition.
“My concern was I just didn’t want to manipulate it and overdramatise it, and make it into some sort of hokey grab at empathy, or whatever, for entertainment,” he said.
“It’s not like I’ve been handed my resignation.”
When asked if acting "still excites" him, Hemsworth said it does, but that he is "going to recharge now".
"I'm going to just not be so focused on the future — and what's next?" he said in the interview.
"I don't mean that in a sort of apathetic way, but there's a stillness to my thinking about it all now."
What is Alzheimer's disease?
Alzheimer’s disease is the most common type of irreversible dementia that causes the brain to shrink and brain cells to die, slowly destroying memory and thinking skills, according to the US National Institute on Aging (NIA).
Healthdirect says it affects up to 1-in-10 Australians over 65 years of age.
Up to 3-in-10 Australians aged over 85 years are affected.
It was the second leading cause of death in Australia in 2020, according to the Australian Institute of Health and Welfare (AIHW).
The AIHW says survival time is affected by age, sex, dementia type and severity at diagnosis, among other factors.
What is the ApoE4 gene?
Certain genes can increase the risk of developing Alzheimer's disease.
ApoE4, or the apolipoprotein E gene, is the strongest risk factor gene for Alzheimer’s disease.
Having one or two copies of this gene increases the risk of developing Alzheimer's, according to the NIA.
It says about 25 per cent of people carry one copy of ApoE4.
Just 2 to 3 per cent carry two copies, making Hemsworth a rare case.
However, even if a person has two copies of the gene, this does not mean they will definitely develop Alzheimer's.
What are the symptoms?
According to Dementia Australia, the most-common symptoms of Alzheimer’s disease include:
- Vagueness in everyday conversation
- Repeatedly saying the same thing
- Taking longer to do routine tasks
- Forgetting well-known people or places
- Changes in ability to plan, problem solve, organise and think logically
- Difficulty processing questions and instructions
- A decline in social skills.
Symptoms will progress differently between people, depending on what areas of the brain are affected.
A person’s symptoms may also change from day to day and can become worse with stress, illness or tiredness.
How is it diagnosed?
Currently there is no single test to diagnose Alzheimer’s disease, according to Dementia Australia.
A diagnosis is made after careful clinical consultation.
The assessment might include:
- A detailed medical history
- A physical examination
- Blood and urine tests
- A psychiatric assessment
- Neuropsychological tests
- Medical imaging, such as an MRI scan.
After eliminating other causes, a diagnosis of Alzheimer’s disease can be made.
Is there a cure? And how is it treated?
Dementia Australia says there is currently no cure for Alzheimer’s disease and no treatment can stop the condition progressing.
However, medications can help stabilise or slow the decline in memory and thinking abilities.
Medications may be prescribed for secondary symptoms such as agitation or depression, or to improve sleep.
Lifestyle changes can also be beneficial, such as:
- Exercising regularly
- Maintaining social contact with friends and family
- Managing stress
- Engaging in activities that stimulate your brain — puzzles, crosswords, learning a new language, etc.