Human Brain Neural Network Cerebral Cortex
A long-term study by University of Edinburgh researchers has uncovered key insights
into how our brains age, revealing that nearly half of the variance in cognitive ability in
older age can be traced back to childhood.

Groundbreaking Scottish research traces cognitive changes from age 11 to 82, providing unprecedented insights into brain health across a lifetime.

A landmark 25-year research program has revealed crucial insights into brain aging and the factors that shape cognitive performance over a lifetime. Published on November 7, 2024, in Genomic Psychiatry, the study is based on the Lothian Birth Cohorts (LBC) research, which uniquely monitored participants’ cognitive abilities from childhood well into their 80s.

Professor Ian Deary and Dr. Simon Cox from the University of Edinburgh present remarkable discoveries that challenge conventional wisdom about brain aging. Their research reveals that approximately half of the variance in intelligence test scores in older age can be traced back to childhood cognitive ability – a finding that raises intriguing questions about the nature versus nurture debate in cognitive development.

Brain Structural Scans From a Selection of Individuals From the Lothian Birth Cohort 1936
Brain structural (MRI) scans from a selection of individuals from the Lothian
Birth Cohort 1936 were taken during Wave 2 (when all participants were
about 73 years old). Panel A shows global atrophy (brain volumetric shrinkage)
ordered from least (top left) to most (bottom right). Panel B shows the total white
matter hyperintensity volume (increasing from top left to bottom right).
Panels A and B are reproduced from Cox and Deary (2022) in Brain Aging, 2,
100032 (74). Panel C shows the white matter pathways of a middle-aged male
adult, identified using diffusion MRI. Views from left to right: superior, lateral,
anterior, inferior. Credit: Ian J. Deary

“What’s particularly fascinating is that even after seven decades, we found correlations of about 0.7 between childhood and older-age cognitive scores,” explains Professor Deary. “This means that just under half of the variance in intelligence in older age was already present at age 11.”

Key Findings in Cognitive Aging and Longevity

Key findings include:

  • Brain aging varies dramatically between individuals of the same age
  • DNA methylation patterns can predict mortality risk
  • Higher childhood intelligence correlates with better survival rates
  • Genetics influences intelligence differently in childhood versus older age

The study’s unique strength lies in its use of the Scottish Mental Surveys of 1932 and 1947, which tested almost every child born in 1921 and 1936 in Scotland. This comprehensive baseline allowed researchers to track cognitive changes across entire lifespans, revealing patterns previously hidden from science.

Variability in Brain Health and the Role of Imaging

Some of the most intriguing findings relate to brain structure and function. Using advanced imaging techniques, the researchers demonstrated substantial variations in brain health among people of the same age. This raises important questions about what factors contribute to these differences and whether they might be modifiable through lifestyle interventions.

The research also challenges several preconceptions about cognitive aging. “We’ve learned that what we often assume are ’causes’ of cognitive decline in older age are sometimes actually ‘outcomes’ of earlier cognitive differences,” notes Dr. Cox. “This fundamentally changes how we think about brain health interventions.”

The findings point to several crucial areas for future investigation:

  • How does early-life cognitive ability influence lifestyle choices that affect brain health?
  • What role do environmental factors play in maintaining cognitive abilities?
  • Can interventions in midlife help preserve cognitive function in later years?

Reference: “Lessons we learned from the Lothian Birth Cohorts of 1921 and 1936” by Ian J. Deary and Simon R. Cox, 7 November 2024, Genomic Press.
DOI: 10.61373/gp024i.0076

Funding: NIH/National Institutes of Health, Biotechnology and Biological Sciences Research Council, Economic and Social Research Council, Wellcome Trust, Royal Society, Medical Research Council, University of Edinburgh, Milton Damerel Trust