60-year study: School tests predict brain health in old age

At the age of 13, participants were tested for inductive thinking — the ability to make decisions and find patterns. The researchers wanted to find out whether high cognitive abilities in adolescence could protect against dementia later in life.

The children with the best test scores were 16 percent less likely to have dementia, even when adjusted for other risk factors such as education and serious illnesses such as heart disease. Tests for other abilities — spatial and verbal — did not affect the likelihood of dementia. This suggests that the protective effect is associated with inductive thinking.

The authors caution that the study does not prove that inductive thinking directly determines dementia risk, but there may be several mechanisms behind this link. Inductive thinking tasks — sorting groups, recognizing patterns — train the fronto-parietal network, a key node in the brain that coordinates working memory and is associated with dementia degradation.

The researchers examined 10,539 Swedish children born in 1948. In 1961, they underwent cognitive tests measuring inductive thinking, verbal and spatial abilities. Inductive thinking tests included completing numerical sequences, identifying patterns, and searching for inappropriate elements. Verbal tasks assessed the understanding of the read and the structure of sentences, spatial – the ability to mentally work with physical objects, for example, puzzle elements. Specifically, the teens were asked to determine the next number in the sequence, select opposite words from the list, and imagine how folding a sheet of metal forms shapes.

The observation continued until November 2025. During this time, dementia was diagnosed in 287 people (2.7%); it is possible that some cases remained unreported. Diagnoses of dementia, heart disease, diabetes and other serious conditions associated with cognitive decline were established from national hospital and mortality registers.

Overall, children with higher scores on inductive thinking tests at age 13 were 16% less likely to have dementia in older age. Each additional score was associated with a 2% reduction in risk. Two other tests showed no such connection. The researchers adjusted the level of education of the participants and their parents.

It also found that while heart disease and diabetes were associated with an increased risk of dementia due to vascular damage and inflammation, 58 percent of participants with dementia did not have these conditions. This suggests that vascular health does not fully explain dementia.

The results were replicated in a cohort of 19,919 people born in 1953: higher scores for inductive thinking were associated with a 15% lower risk of dementia.

In addition to training brain structures suffering from dementia, inductive thinking may be related to "system integrity" - when people with stronger cognitive functions at an early age have better functioning of multiple systems, including the brain, heart and metabolic health.

The authors caution that they could not account for other factors associated with dementia: prenatal health, genetics, adult lifestyle and specific dementia subtypes. Future research will help further assess this relationship and explore whether cognitive development in childhood can prevent dementia.