Study Finds Causal Link Between More Education and Lower Dementia Risk

Staying in school for just one additional year may lower the risk of developing Alzheimer’s disease and related dementias (ADRD) later in life, according to a study published in the Proceedings of the National Academy of Sciences (PNAS).

For years, observational data suggested that highly educated people have healthier brains, but critics argued this was likely due to “confounders”—better genetics, childhood circumstances, or socioeconomic factors. However, because the UK government changed the law for one specific group of children, researchers could isolate education as the primary variable.

The 1972 Law That Became a Medical Lab

The catalyst for this discovery was the 1972 Raising of School-Leaving Age Act (ROSLA). This legislation increased the minimum age for dropping out of school in England, Scotland, and Wales from 15 to 16. The cutoff was absolute: students born after September 1, 1957, had to stay in school, while those born just days earlier could leave.

Health economist Silvia Barcellos from the University of Wisconsin-Madison and her team used this strict date to create a control group. They compared people born just before the cutoff to those born just after. Since these two groups were virtually identical in terms of era and socioeconomic background, any difference in their brain health 50 years later could be attributed to that single extra year of schooling.

Using data from the UK Biobank, the team tracked over 100,000 residents. The reform led to a 14% increase in the number of students staying in school until 16. When these individuals reached age 65, the data showed a clear trend: those born after the September 1, 1957, deadline had a lower cumulative incidence of ADRD.

Rewriting the Genetic Script

The research found that education helps those with high genetic risks for Alzheimer’s.

Study Finds Causal Link Between More Education and Lower Dementia Risk — Photo: AARP

Among those born before the law changed, high genetic risk translated directly into a higher incidence of dementia. But for the “treated” group—those forced to stay in school until 16—that extra year of education was associated with a reduction in dementia, even for the high-risk individuals.

This suggests that modifiable life experiences can actually buffer the brain against inherited susceptibility.

Cognitive Reserve and Socioeconomic Luck Explain Education Benefits

Why does one year of high school matter five decades later? There are two competing theories. The first is “cognitive reserve,” a concept discussed by Dr. Yaakov Stern of Columbia University. The idea is that education expands and strengthens brain networks, allowing the brain to continue functioning even as physical decay or disease sets in.

The second theory is more pragmatic. Someone who left school early, for example, may have grown up in poverty and, as a result, had limited access to health care and, as an adult, may be more likely to smoke or have poor cardiovascular and metabolic health.

However, the study’s numbers come with a caveat. The researchers calculated that the extra year reduced ADRD incidence by about 0.88 percentage points.

Lifelong Learning May Offset Limited Formal Education

You cannot go back and add a year of high school at age 60. This is where the “modifiable risk” argument becomes tricky. While you can quit smoking or treat high blood pressure today, you cannot rewrite your formal educational history.

The counter-argument is that the benefit of education is intellectual stimulation, not the diploma itself. If the brain’s resilience is built through learning, then lifelong learning—reading, new hobbies, or vocational training—might offer a similar protective effect to that found in the 1970s cohort.

There is also the limitation of age. Because the study capped participants at age 65, it remains unclear how these protective effects hold up in the very elderly, where dementia rates spike. The researchers plan to continue following the cohort to see if the “education shield” lasts.

The evidence suggests that the environment we create for young people—and the laws that keep them in learning environments—has a ripple effect that lasts a lifetime. A policy decision made in a 1972 parliament may have fundamentally altered the biological trajectory of thousands of brains.