Long-Term Study Provides Insights into Cognitive Aging: Daily Dose

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On November 11, 2024, we reported on findings from a 25-year research program published in Genomic Psychiatry that revealed insights into healthy brain aging and what factors influence cognitive performance throughout life.

The study

The review drew data from the long-running Lothian Birth Cohorts (LBC) studies, which are 2 longitudinal studies based on individuals born in 1921 (LBC1921) and 1936 (LBC1936) in Scotland. These studies traced cognitive aging, with participants originally tested in childhood through the Scottish Mental Surveys. The LBC1921 began in 1999 with 550 participants aged 79 years, while LBC1936 started in 2004 with 1091 participants aged 70 years. Both cohorts have contributed extensive data on cognitive functions, genetics, brain imaging, and health, including retest results from the same intelligence test they took as children.

The findings

The most recent data on the 2 cohorts suggests that higher childhood intelligence is linked to a longer, healthier life, including significantly reduced risk of cardiovascular disease, stroke, and dementia of 20% to 25%. Children who scored higher on intelligence tests at age 11 tended to exhibit better cognitive function in older age. These findings suggest that cognitive abilities developed early in life play a crucial role in shaping overall health outcomes in later years.

Also, the studies suggested that younger DNA methylation age at baseline (measured at ages 70 for the LBC1936 and 79 for the LBC1921) was associated with longer lifespan. This suggests that the patterns of DNA methylation can reflect biological aging processes and may serve as a biomarker for longevity.

The findings underscored the complex interplay between genetic, environmental, and lifestyle factors in shaping cognitive aging. The studies revealed that while genetic predispositions are important, lifestyle choices and psychosocial factors also significantly influence cognitive outcomes.

The study also highlighted the importance of brain white matter in cognitive functioning, emphasizing that healthy white matter across different brain regions was correlated with better cognitive performance. Researchers found that people with healthier white matter connections tended to experience slower cognitive decline over time. Changes in white and grey matter also contributed to differences in cognitive aging, with various brain regions showing different degrees of involvement.

Authors' comment

"We…hope that our discoveries and incremental contributions to the fields in which we work will help people to make better choices regarding healthy lifestyles and provide understanding regarding contributions to individual differences in cognitive and brain ageing and ageing more broadly."

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