WEDNESDAY, Jan. 18 (HealthDay News) -- Genetic factors account for some of the changes in intelligence that occur between childhood and old age, according to a letter published online Jan. 18 in Nature.
Ian J. Deary, Ph.D., from the University of Edinburgh in the United Kingdom, and colleagues investigated the genetic and environmental contributions to stability and change in intelligence from childhood to old age. Genetic (co)variance was estimated from genome-wide single nucleotide polymorphism (SNP) data from 1,940 unrelated individuals whose general cognitive ability was measured at age 11 years and at age 65, 70, or 75 years.
Based on a univariate analysis, the researchers found that 0.24 of the variation in cognitive aging could be accounted for by causal genetic variants in linkage disequilibrium with common SNPs. Based on a bivariate analysis, the genetic correlation between intelligence in childhood and old age was estimated to be 0.62.
"Genetic factors seem to contribute much to the stability of intelligence differences across the majority of the human lifespan," the authors write. "However, our estimates suggest that genetics and environment could each contribute substantially to the covariance between intelligence at age 11 and old age, and that genetic factors might have a role in cognitive change between the two stages of the life course."
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