The study, published in the journal Neurology and carried out using Insight 46, a substudy of the MRC National Survey of Health and Development, also found that education level and socioeconomic status were predictors of thinking and memory performance.
‘Finding these predictors is important because if we can understand what influences an individual’s cognitive performance in later life, we can determine which aspects might be modifiable by education or lifestyle changes like exercise, diet or sleep, which may in turn slow the development of cognitive decline,’ said study author Professor Jonathan Schott, of University College London and the American Academy of Neurology.
The study involved 502 people all born during the same week in 1946 in Great Britain who took cognitive tests when they were eight years old. Between the ages of 69 and 71, participants took thinking and memory tests again. One test, similar to a test they completed as children, involved looking at various arrangements of geometric shapes and identifying the missing piece from five options. Other tests evaluated skills like memory, attention, orientation and language.
Participants had positron emission tomography (PET) scans to see if they had amyloid-beta plaques in the brain associated with Alzheimer’s disease. They also had detailed brain magnetic resonance imaging scans (MRI).
Researchers found that childhood thinking skills were associated with scores on the cognitive tests taken more than 60 years later. For example, someone whose cognitive performance was in the top 25% as a child was likely to remain in the top 25% at age 70. Even accounting for differences in childhood test scores, there was an additional effect of education. For example, participants who completed a college degree scored around 16% higher than participants who left school before the age of 16.
Having a higher socioeconomic status also predicted slightly better cognitive performance at age 70, but the effect was very small. For example, those who had worked in professional jobs tended to recall an average of 12 details from a short story, compared with 11 details for those who had worked in manual jobs. Women performed better than men in tests of memory and thinking speed.
In addition, researchers found that participants with amyloid-beta plaques had lower scores on cognitive testing. For example, on the missing pieces test, they scored 8% lower on average. In other words, they got 23 out of 32 items correct on average – two points lower than participants without amyloid-beta plaques. However, the presence of these plaques was not associated with sex, childhood cognitive skills, education or socioeconomic status.
‘Our study found that small differences in thinking and memory associated with amyloid plaques in the brain are detectable in older adults even at an age when those who are destined to develop dementia are still likely to be many years away from having symptoms,’ said Professor Schott. ‘It also found that childhood cognitive skills, education and socioeconomic status all independently influence cognitive performance at age 70. Continued follow-up of these individuals, and future studies, are needed to determine how best to use these findings to more accurately predict how a person’s thinking and memory will change as they age.’
Speaking to The Times newspaper about the study, Professor John Gallacher, Director of DPUK and Professor of Cognitive Health at Oxford University, said parents who helped build up their children’s thinking and problem-solving skills could make them more resilient to dementia. He added: ‘There is every argument for saying that if you give a child the best start in life with a rich, cognitively stimulating environment, the benefit will persist throughout adulthood, potentially through to better cognitive health in old age. The idea of reading imaginative stories with your child, solving problems, creating a learning environment where their mental life is enjoyed… The richer your child’s cognitive life is, the richer their adult cognitive life will be and the lower the risk of dementia.’