Leaving School at 15 or Studying Until 16: The Difference in Dementia Risk 50 Years Later

Could the time spent in school affect health decades later?

People who receive longer education are less likely to be diagnosed with dementia in old age. This relationship has been known for some time. However, this alone does not conclusively prove that "education reduces dementia risk" because factors like family economic status and childhood living environment affect both education and health.

Researchers focused on the educational reform in the UK over half a century ago.

The minimum age to leave school was raised from 15 to 16. Research utilizing the differences created by this policy change has provided new evidence on the relationship between education and dementia.

The study introduced by the German newspaper WELT is not a simple story of "higher education means no dementia." Rather, it suggests that opportunities provided in youth may impact health later in life.

Differences in Education Duration Created by Birthday Cutoffs

The stage for the research was the UK in 1972.

In England, Scotland, and Wales, children born on or after September 1, 1957, were required to stay in school until at least 16. Those born before the cutoff could leave school at 15 as before.

Despite having similar birthdays and living in the same era, the required education period differed due to the system.

Researchers compared those around this cutoff to examine the impact of education duration on later health. This is a so-called "natural experiment" using policy changes.

Of course, not everyone's school attendance was extended by a year. For those already planning to study beyond 16, the raised minimum age had no direct impact. The study found that the reform increased the proportion of people staying in school until 16 by about 14 percentage points.

Thus, the focus is not on the difference between university graduates and non-graduates, but on the changes in people who received additional education due to the policy.

Differences Appeared in Diagnosis Records Decades Later

The research was conducted by teams from the University of Wisconsin-Madison, the University of Southern California, and the University of Michigan. The paper was published in the Proceedings of the National Academy of Sciences (PNAS).

Researchers used data from the UK Biobank, a large-scale research database in the UK. The analysis involved up to about 107,000 people, depending on the conditions.

Dementia was identified by combining hospital records, death registrations, and self-reported medical histories. The study reported that receiving additional education due to the reform led to a decrease in later diagnoses of Alzheimer's disease and related dementias.

A strength of this study is that it does not simply compare "people with longer education" to "those with shorter education."

When comparing groups with different family environments and personal characteristics, it is difficult to separate whether differences in results are due to education or other factors. The method using the policy boundary addresses this issue.

However, this is not an experiment that directly tracked changes in the brain from school experiences. The evidence obtained is about the relationship between educational reform and subsequent dementia diagnoses.

Even with High Genetic Risk, Results Were Not Fixed

Another important finding is the relationship with genetic risk.

The study combined genetic information and found that even those with a high genetic predisposition to dementia showed a decrease in diagnoses due to additional education. The educational reform weakened the link between genetic risk and diagnosis.

For those with family members who have experienced dementia, this is likely a highly relevant result.

However, interpreting this as "education can erase genetic effects" is an overreach. This study does not predict individual onset or show the same effect for all hereditary dementias.

Nonetheless, the point that the future is not determined solely by genetic predisposition, and that environment and opportunities in life can also play a role, is significant.

This broadens the perspective on dementia prevention to earlier stages of life, not just old age.

Why Education Affects Dementia: It's Not Just About "Using Your Brain"

Reading this news, one might think, "It's because studying trains the brain."

However, researchers have not identified what specifically led to the decrease in diagnoses.

A longer education period might change the jobs one can get or the income one earns. It might increase opportunities to think at work or change living environments and relationships.

According to the original article, among the subjects of this study, additional education was accompanied by increased household income in later years and fewer strokes and heart attacks. However, it is unclear which of these explains the reduction in dementia diagnoses.

Here, two issues need to be separated.

One is the possibility that the original family environment affected both education and health. The other is the possibility that education changed subsequent jobs and income, thereby affecting health.

If it's the latter, changes in income and jobs could also be part of the educational effect. It is not necessarily possible to explain the results by isolating the content of school lessons.

Interest in the Research on Social Media, Questions from Personal Experiences in Reader Comments

How is this research being received online?

On LinkedIn, Jessica Leight introduced the research activities of co-author Sneha Nimmagadda, highlighting the study examining the relationship between education and dementia risk using compulsory education reform as an interesting research topic.

However, this is a post introducing a researcher's work and not the reaction of general users who read the WELT article. It is mentioned as a working paper in the post and should be distinguished from the reactions after the article's publication.

On the other hand, reader comments on the WELT article provided included opinions rooted in personal life experiences. The following is a summary of their gist and does not represent the overall opinion on social media.

"Even Highly Educated People Can Get Dementia"

One reader pointed out that even scholars have developed dementia, indicating that education does not completely prevent its onset.

This perspective is important when reading the research.

Lowering the diagnosis risk as a group is different from preventing each individual from developing the condition. Even if someone with a long education develops dementia, it does not negate the research results.

At the same time, this research cannot be used to evaluate the learning or efforts of those who have developed dementia.

"Years in School Don't Measure Life's Learning"

Another reader shared the experience of their father, who continued reading despite not having a long formal education. The reader also engages in language learning and playing musical instruments.

Such personal stories do not scientifically prove the medical effects of individual activities. However, they convey a desire not to define "education" solely by diplomas.

Even after leaving school, people learn through work, hobbies, and conversations with others. The richness of this and the effect of the measured school attendance period are related topics but not the same.

It is important to note that this study alone does not suggest that starting reading or playing instruments will have the same effect.

"Was It Staying in School or Avoiding Early Work That Mattered?"

Some readers questioned whether staying in school was important or if avoiding a life of working from age 15 was the key factor.

Other comments focused on elements associated with school, such as group life and daily routines.

These questions align with the research challenge of the unexplained mechanism of effect. However, not understanding the mechanism is not the same as being unable to estimate the effect of the policy.

Even if extending education had an effect, further investigation is needed to determine which experiences were effective.

Not Rushing to Conclude "What Percentage Decreases"

There are also significant limitations to this study.

The main evaluation point was the end of 2022, when the first generation affected by the reform turned 65. The results have not been observed until the age when dementia becomes more prevalent.

At this point, there are still few diagnosis cases, making it difficult to precisely determine the magnitude of the educational effect. Additional tracking is needed to see if the difference persists as subjects age.

Furthermore, due to the few diagnosis records, it cannot be concluded that the pathological changes in the brain were reduced to the same extent. The way symptoms manifest and the process of diagnosis remain issues to be examined.

Additionally, this is the result of extending school attendance from 15 to 16 in the UK in the 1970s. It is not guaranteed that increasing enrollment in universities or graduate schools in modern Japan will have the same effect.

The value of this study lies not in showing a universal preventive effect number but in demonstrating that intervention in education can affect dementia diagnoses decades later.

What Japan Should Consider: "Conditions for Learning" Over Academic Competition

So, how should this research be interpreted in Japan?

There is no need to simplistically think, "Let's keep children in school as long as possible" or "Having more qualifications is reassuring." The research dealt with the impact of expanded educational opportunities due to policy.

For implications for Japan, attention should be directed towards creating an environment where learning does not have to be abandoned due to family circumstances.

Not just tuition, but living expenses, commuting burdens, and roles at home. Continuing education involves conditions that cannot be resolved by personal motivation alone.

Should the value of educational support be judged only by enrollment rates or income immediately after employment? Can it be considered an investment that supports people's health and lives over a longer time frame? This study raises such questions.

Interest in adult re-education and community interaction will likely expand. However, separate verification is needed for their effects. This study cannot be used to guarantee the effectiveness of specific courses or "brain training" products.

The experience of staying in school for one more year may have changed subsequent jobs and lives, potentially linking to health decades later.

The value of education does not necessarily become apparent at the time of graduation. Ensuring conditions where everyone can learn has long-term significance that is not yet fully visible.

Sources and References

1. WELT: Referenced for research overview, researcher explanations, and unexplained mechanisms linking education and health.
   https://www.welt.de/gesundheit/article6ae30800063ab7e38a99faa2/demenz-forscher-belegen-erstmals-wie-wichtig-bildung-fuer-gehirngesundheit-ist.html

2. PNAS Published Paper "Education reduces dementia incidence and mitigates genetic risk": Primary source for analysis method using educational reform, number of subjects, 14-point increase in attendance rate, evaluation point, and research limitations.
   https://pmc.ncbi.nlm.nih.gov/articles/PMC13715751/

3. University of Southern California - USC Schaeffer: Explanation by the research team. Describes design to investigate causality, relationship with genetic risk, and uncertainties in mechanisms and effect size.
   https://schaeffer.usc.edu/research/more-education-reduces-dementia-risk-decades-later/

4. National Institutes of Health (NIH): Announcement by the research support organization. Referenced for research overview using multiple diagnosis records and the necessity of tracking until older ages.
   https://www.nih.gov/news-events/news-releases/extra-year-secondary-school-lowered-dementia-diagnoses-later-life

5. LinkedIn - Public Post by Jessica Leight: SNS post mentioning research on compulsory education reform and dementia risk in the introduction of a co-author's research. Not treated as a direct reaction to the WELT article or as a representation of general public opinion.
   https://www.linkedin.com/posts/jessicaleight_todays-cool-young-researcher-is-sneha-nimmagadda-activity-7495116029480579074-YAxk