Dementia is Not a "One-Person Disease"—Invisible Health Risks Extend to Spouses

Dementia is often thought of as a problem that only affects the diagnosed individual.

Memory loss increases, understanding time and place becomes difficult, and tasks like household chores and financial management that were once routine become challenging. As the condition progresses, recognizing family faces and names may become impossible. While these changes are experienced by the patient, the spouse who supports their daily life closely also gradually loses their everyday life.

Responding to repeated confirmations from morning to night, managing medication and hospital visits, being vigilant against falls and wandering, and taking over household finances and administrative tasks. Being woken up multiple times at night, reducing outings and social interactions, and postponing one's own health issues.

As a result, the health of the caregiving wife or husband may also be compromised.

A large-scale study by a Taiwanese research team suggests that dementia should be viewed not only as an "individual patient problem" but as a "health issue affecting couples and entire households."

Study of About 1 Million People Shows Increased Risk After Spouse's Onset

The study analyzed data from Taiwan's public health insurance database from 1998 to 2022.

The subjects were about 1 million married individuals living in Taiwan. The research team extracted approximately 119,000 women and 72,000 men whose spouses were newly diagnosed with dementia and compared them with a control group with similar age, gender, income, and residential area.

The analysis showed that individuals whose spouses had dementia were more likely to be diagnosed with dementia themselves compared to those whose spouses did not have dementia.

In models adjusted for age, chronic diseases, medical institution usage, number of children, etc., the relative risk was 74% higher for women and 69% higher for men.

However, this figure does not mean "if a spouse gets dementia, there is a 74% chance you will too."

Looking at the actual onset rate over five years, 6.47% of women whose spouses had dementia developed it, compared to 3.72% in the control group. For men, it was 9.24% and 5.75%, respectively.

In other words, the absolute difference over five years was 2.75 points for women and 3.49 points for men.

The expression "risk increases by 74%" may sound extremely alarming, but it is important to separate relative risk from actual onset probability.

Nevertheless, the consistent difference confirmed by comparing hundreds of thousands of subjects is significant. It suggests that a spouse's dementia diagnosis could be an opportunity to check the other person's health status.

Dementia Does Not "Infect" Between Couples

The most important caution about this study is the misconception that "dementia is contagious to spouses."

Dementia is not a disease that spreads from person to person like a cold or influenza. It is a general term for a decline in cognitive function due to various diseases and brain disorders, such as Alzheimer's disease, vascular dementia, and Lewy body dementia.

What the study showed was a statistical correlation between one spouse developing dementia and the other being diagnosed later.

The research team suggested several pathways that could create this correlation.

Couples Share Long-Standing Lifestyle Habits

The first consideration is the shared lifestyle habits such as diet, exercise, sleep, drinking, and smoking.

Couples who have lived together for many years often eat the same meals, sleep at similar times, and spend holidays together. If one does not have an exercise habit, the other may also have fewer opportunities to be active. If dining out or consuming salty foods is frequent, the impact may extend to both.

Hypertension, diabetes, obesity, lipid abnormalities, lack of exercise, and smoking are related not only to the heart and blood vessels but also to future cognitive function.

The longer the time spent living together, the more similar both healthy and unhealthy habits become. This accumulation may affect the dementia risk for both spouses.

Conversely, when improving lifestyle habits, it may be easier to continue if approached as a couple.

Instead of one person starting to exercise alone, they can take walks together. Instead of just one person changing their diet, they can review the entire household's menu. Lifestyle habits that place the couple in the same risk environment can also be transformed into habits that protect both.

The Impact of Couples with Similar Backgrounds

The second possibility is that the couple had similar factors even before becoming a couple.

People tend to choose partners with similar educational backgrounds, income, occupations, living areas, and attitudes towards health.

For example, it is not uncommon for people who like exercise, those who dine out frequently, or those who met in the same region or workplace to marry. If the duration of education or economic situation is similar, access to medical care and exposure to health information may also be similar.

When considering the brain's resilience to dementia, the concept of "cognitive reserve," formed through education, work, and intellectual activities, is also emphasized.

It's not just that the living environment suddenly affects the other after one spouse develops dementia. The similar backgrounds before marriage and the shared environment after marriage may have accumulated over the years.

Chronic Stress on the Caregiving Spouse

The third possibility, and a major issue raised by this study, is the burden of caregiving itself.

Dementia caregiving requires not only physical care but also constant judgment and vigilance.

Forgetting meals and attempting to eat multiple times. Insisting they haven't taken their medication. Complaining about losing wallets or bankbooks. Getting lost in familiar places. Feeling anxious or confused at night.

The caregiver must explain the situation each time, reassure the person, and respond to prevent accidents. However, the explained content is quickly forgotten, and the same interactions are repeated.

In the caregiver's mind, there is a constant vigilance of "will they fall," "have they gone outside," "did they take their medication," "did they turn off the stove."

Such a state can continue not for weeks but for years.

Chronic stress, combined with sleep deprivation, depression, anxiety, social isolation, lack of exercise, and irregular meals, can place a significant burden on the caregiver's mind and body.

The research team suggested that psychological distress, depression, sleep disorders, isolation, metabolic abnormalities, inflammation, and unhealthy behaviors might be related to the spouse's cognitive decline.

However, the study did not directly measure caregiving time, sleep time, stress hormones, etc. Therefore, it cannot be concluded that "caregiving stress caused dementia."

Nevertheless, the issue raised about not neglecting the caregiver's health carries significant weight.

Larger Differences in Households with Lower Income and Fewer Children

The study also found trends varying by income and the number of children.

For those with lower income or fewer children, the absolute risk difference of developing dementia when a spouse had it was larger. Conversely, for those with higher income and more children, the difference tended to be smaller.

The background consideration is the difference in resources available for caregiving.

With financial leeway, it is easier to use home care, day services, short-term stays, and household support. Options to secure rest time for the caregiver or entrust responses to professionals increase.

If children or relatives are nearby, they may be able to share responsibilities like accompanying hospital visits, shopping, and administrative procedures.

Conversely, if the household budget is tight and there are few family members to rely on, almost all roles concentrate on one spouse.

Of course, having more children does not necessarily mean they will help with caregiving. They may live far away or have distant relationships. The number of children in the study does not directly indicate actual caregiving participation.

Nonetheless, not concentrating caregiving on one person is undoubtedly important for protecting the caregiver's health.

Anxiety of "Am I Also Developing Dementia?" Seen on Social Media

Even before this study was published, posts expressing concerns like "I've been forgetting things more since I started caregiving" have repeatedly appeared on social media and online caregiver communities.

In overseas dementia caregiving communities, voices with the following sentiments have been posted:

"Since I started caregiving, I've been forgetting what I heard right after hearing it."

"I'm managing not only my schedule but also the other person's medication, accounts, taxes, and medical appointments. Worries are constantly running through my mind."

"Continuous sleep deprivation and tension make me feel like my brain isn't working anymore."

"I understand the expression that dementia takes away the lives of two people."

These are personal experiences, not diagnoses by doctors. Strong stress, sleep deprivation, depression, anxiety, and menopausal changes can also temporarily reduce concentration and memory.

Feeling forgetful should not immediately lead to a dementia diagnosis.

On the other hand, thinking "it's natural to be tired because I'm caregiving" and enduring all symptoms is also dangerous. If changes in the caregiver's condition or cognitive decline are overlooked, the couple's life may simultaneously become unsustainable.

On social media, there are many encouraging responses to caregivers expressing anxiety, such as "please take a break," "connect with support groups," and "it's not a lack of love if you can't continue caregiving alone."

What becomes apparent is that caregivers are seeking not just moral support but actual time to rest and someone to take over their roles.

These public posts are not a public opinion survey but voices from communities where people troubled by dementia caregiving tend to gather. They do not represent the opinion of society as a whole but indicate the urgency caregivers feel, which is difficult to see from statistics alone.

Pressure of "It's Natural for Family to Provide Care"

In dementia caregiving, there is also the issue that caregivers find it hard to admit their limits.

They feel guilty about placing a long-term partner in a facility. Using external caregiving services makes them feel as if they are abandoning their responsibility. They may be told by others, "You should support them to the end because you are a couple."

However, there are physical and mental limits to one elderly person continuing to provide 24-hour monitoring and assistance.

If the caregiver collapses, the patient themselves will also be unable to maintain their life.

Using caregiving services or short-term stays is not proof of a lack of love. Rather, it is a means to maintain the couple's life for a longer time.

Taking a break is not escaping from caregiving; it is a necessary action to continue caregiving.

Regular Health Checks for Caregivers Too

The practical response suggested by this study is to view not only the person diagnosed with dementia but also their spouse as subjects of medical and caregiving attention.

For example, during the patient's examination, also check the spouse's sleep, appetite, mood, blood pressure, diabetes, exercise, alcohol consumption, and social interactions.

If the caregiver feels "my head isn't working recently," don't just assume it's fatigue or sleep deprivation; consult a primary care doctor. If necessary, check cognitive function, depression, anxiety, medication status, hearing, etc.

Within the family, it's important to divide roles specifically rather than having vague promises like "I'll help if something happens."

Who will be responsible for hospital visits? Who will handle shopping, meals, financial management, and administrative procedures? Who will be contacted in emergencies? Can a day be set for the caregiver to rest?

If it's difficult for the family alone, it's necessary to connect with community comprehensive support centers, care managers, medical institutions, dementia disease medical centers, family associations, etc.

Consulting doesn't have to be only when you're completely stuck. If you establish a relationship with supporters early on, it will be easier to respond when the condition progresses.

Not All Dementia Risks Can Be Prevented

It is estimated that about 57 million people worldwide live with dementia, and approximately 10 million new cases occur each year.

There are significant risks that cannot be changed by oneself, such as age and genetic factors. Some people develop dementia despite living healthily, while others do not develop it despite having lifestyle issues.

Therefore, individuals with dementia and their families should not be blamed with statements like "your lifestyle was bad" or "you didn't try hard enough."

On the other hand, international research has identified modifiable factors related to dementia, such as education, hearing loss, hypertension, smoking, obesity, depression, lack of exercise, diabetes, excessive drinking, head injury, air pollution, social isolation, vision impairment, and high LDL cholesterol.

While not all dementia can be prevented, managing blood pressure and diabetes, staying active, maintaining social connections, and addressing hearing and vision problems are meaningful for preventing other diseases as well.

For caregivers, in addition to these, "securing time away from caregiving" becomes important.

Limitations of the Study—Causality is Still Unknown

This study is large-scale but has several important limitations.

Firstly, it is an observational study using medical insurance records, and it does not prove that a spouse's dementia directly caused the other spouse's dementia.

Secondly, the dementia diagnosis is based on codes in medical records, and not all patients were confirmed with brain imaging or biomarkers.

Thirdly, there was no detailed information on educational history, exercise, diet, smoking amount, and social participation.