One Extra Year of School Tied to Lower Dementia Risk Later in Life
WHO:
The Washington Post - Leandro Carvalho is an associate research professor of economics at the University of Southern California.
The Washington Post - The study examined adults who stayed in school an extra year as teenagers and compared their later dementia risk with that of people who left school sooner.
ScienceAlert - The research was conducted by health economist Silvia Barcellos of the University of Wisconsin-Madison and fellow researchers; co-author Leandro Carvalho is a health economist at the University of Southern California.
ScienceAlert - Researchers used UK Biobank data and examined participants’ DNA, including the APOE4 Alzheimer’s risk gene, to group participants by high or low genetic risk for Alzheimer’s Disease and Related Dementias (ADRD).
WHAT:
ScienceAlert - The findings were published in the journal PNAS.
The Washington Post - Researchers said they hope to continue following the relatively young study cohort.
The Washington Post - A study found that adults who stayed in school an extra year as teenagers had a lower risk of dementia later in life.
The Washington Post - Earlier research linked more education with lower dementia risk but could not distinguish the effect of schooling itself from socioeconomic factors that also affect dementia risk.
ScienceAlert - Researchers reported evidence of a causal link between education and reduced ADRD incidence, describing the study as the first evidence of its kind.
ScienceAlert - Their calculations estimated that one additional year of schooling reduced ADRD cumulative incidence in the cohort by approximately 0.88 percentage points. The researchers said this estimate was implausibly large because ADRD prevalence in the sample was below 1 percent overall.
ScienceAlert - The researchers said they could estimate the direction of education’s causal effect, but not its precise magnitude, because ADRD was rare in the relatively young cohort and the research design required very large samples for precise estimates.
ScienceAlert - Participants at high genetic risk had significantly greater ADRD incidence if born before the school-leaving-age change; among those born after it, an extra year of schooling was associated with a significant reduction in dementia incidence in the high-risk group.
ScienceAlert - Carvalho said: “Genes help shape disease risk, but they do not necessarily determine the outcome.”
WHERE:
ScienceAlert - The school-leaving-age reform applied in England, Scotland, and Wales.
WHEN:
ScienceAlert - The UK’s Raising of School-Leaving Age Act took effect in 1972, increasing the minimum school-leaving age from 15 to 16.
ScienceAlert - The reform affected students born after September 1, 1957; students born immediately before the cutoff could leave school at 15, while those after it had to stay until 16.
ScienceAlert - The study reported health effects roughly 50 years after the additional schooling; affected students were in their late sixties at the time described.
WHY:
ScienceAlert - The researchers suggested that additional schooling may have raised qualifications, income, and occupational status, with advantages accumulating over decades and potentially protecting against neurodegeneration.
ScienceAlert - Carvalho said the findings suggest changeable life experiences and circumstances may affect whether inherited susceptibility develops into disease, and that identifying protective interventions is an important direction for future research.
HOW:
ScienceAlert - The research team also cited an earlier study that used wartime sugar rationing in the United Kingdom as a historical experiment to investigate long-term health effects.
ScienceAlert - Researchers treated the 1972 reform as a natural experiment, comparing later-life health among students required to stay in school until 16 with peers born just before the cutoff who could leave at 15.
ScienceAlert - The researchers used the September 1, 1957 birth-date cutoff to assess whether ADRD incidence showed a corresponding discontinuity; they attributed any such change to the schooling difference created by the policy.
(UPDATED October 29, 2026 14:07 UTC)
A study found that an extra year of schooling during the teenage years was linked to a lower risk of dementia later in life, including for people with high genetic risk. Researchers used the 1972 school-leaving-age reform in England, Scotland and Wales as a natural experiment, comparing people who had to stay in school until 16 with those born just before the cutoff who could leave at 15. Published in PNAS, the research suggests education may influence whether inherited risk leads to disease, but the team said dementia was too rare in the relatively young group to estimate the effect’s precise size.
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(UPDATED October 29, 2026 13:06 UTC)
A study using a 1972 school-leaving-age reform in England, Scotland and Wales found that an extra year of schooling was linked to lower dementia risk later in life, including among people with high genetic risk. Researchers compared adults born just before and after a cutoff that required some students to stay in school until 16, and analyzed UK Biobank health and DNA data. They said the findings support a protective effect of education, but the study could not determine its precise size because dementia was rare in the relatively young group.