Research has shown that marriage can be a life-saving factor in medical crises, whether for financial assistance, practical caregiving, or emotional support.
However, in the case of one incurable illness, it has been found to have the opposite effect.
A new study has shown that being married to someone with dementia could increase one’s risk of getting the disease themselves, compared to couples where neither has it.
Highlights
- A new study has found that having a spouse with dementia is associated with a high increase in one's own risk.
- Researchers claimed that caregiving stress, isolation, and declining health are potential contributors to the elevated risk.
- Public figures such as Emma Heming Willis and Jay Leno have spoken about the emotional toll of caregiving.
The World Health Organization’s (WHO) data claims that dementia is currently the seventh leading cause of mortality worldwide and one of the major causes of disability and dependency among older people.
Having a spouse with dementia may increase the other partner’s risk of developing the condition
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Dementia, an umbrella term for brain damage and the gradual loss of cognitive function, causes a decline in mental ability severe enough to interfere with daily life.
According to the WHO, 57 million people suffered from it in 2021, and the number is expected to reach 78 million in 2023 and 139 million in 2050.
Alzheimer’s Disease International says there are over 10 million new cases of dementia each year worldwide, implying one new case every 3.2 seconds.
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The new study, published in the Journal of the American Medical Association (JAMA) on July 20, 2026, examined data from about 1 million people in Taiwan to determine dementia risk among married couples and the factors that aggravate or mitigate it.
The researchers found that women had a 74% increased risk of dementia if their partners had it, while men had a 69% higher chance of developing it if their partner had the condition.
Once the researchers accounted for extra risk, such as age, they found the increased risk corresponded to an additional 2.75 cases of dementia per 100 women and 3.49 cases per 100 men over five years.
Researchers pointed to 3 factors behind dementia risk in couples
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Dementia is not contagious, but the study identified three reasons spouses may develop it within years of each other. First is assortative mating, and the second is a shared lifestyle.
People often seek out partners from similar socio-economic backgrounds, which shapes lifestyle preferences and access to healthy food, exercise, and social life that can delay dementia.
The third and most impactful reason the study derived was the role of caregiving played by one partner.
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When one spouse develops dementia, the other steps in as the primary caregiver in about 25% of the cases, according to a 2020 report by the Population Reference Bureau.
Family Caregiver Alliance says that 30%-40% of dementia caregivers suffer from depression and emotional stress, and a third of them do so while dealing with declining health themselves.
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Past studies have shown that spouses who are primary caregivers for their partners with dementia get the illness more often in the future. The development was attributed to the stress, isolation, and mental health battles associated with caregiving.
However, the previous studies were based on “relatively small or regional samples,” Dr. Chi-Shin Wu, one of the researchers associated with the new study, told ABC.
Dr. Wu further added that the new study “did not assume that every spouse was the primary caregiver.”
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This would likely improve understanding of the disease among married couples, according to Simone Reppermund, an expert in cognitive disorders at the University of NSW's Center for Healthy Brain Aging.
Reppermund, who was not involved in the study, told ABC, “The researchers controlled for a lot of factors that are important to control for, which is a real strength of this study, and still the risk of dementia was a lot higher.”
Jay Leno and Emma Heming Willis were among the celebrities highlighting the strain of dementia caregiving
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In recent years, several public figures have spoken openly about the emotional toll of caring for a partner while watching them struggle with the disorder.
Bruce Willis, who retired from acting after being diagnosed with aphasia in 2022, was later diagnosed with frontotemporal dementia (FTD).
Throughout his health journey, his wife, Emma Heming Willis, his primary caregiver, has shared candid reflections on the challenges he has faced while also raising awareness.
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In May 2026, she admitted in an interview with Today that she didn’t initially realize the impact of caregiving and made the mistake of neglecting her health. Now, she makes time for herself, be it gardening, exercise, or catching up with her friends.
“(Caregivers) can ask for help,” Emma said. “They’re not a failure if they need the help. It’s OK to bring people in to support you and your loved one.”
“It’s important for us to be able to put our health first, so that we can continue to care for the people that we love.”
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Former Tonight Show host Jay Leno has also spoken about caring for his wife, Mavis Leno, after she was diagnosed with advanced dementia.
“The idea that you get married and you take these vows, nobody ever thinks they’ll be called upon to act on them, you know?” Jay told Today in November 2025. “You know that part for better or worse. But even the ‘worse’ is not that bad.”
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