15% of the population carries the protein creating APOE4 allele gene which makes them as much as 3 times more likely to develop the disease, and according to University of California research those carrying this gene scored lower on IQ tests during childhood and adolescence; the negative impact on IQ was more prevalent in girls than boys.
Data was compiled and analyzed from 2 previous studies involving 1,321 participants between the ages of 6-18 years old, with a gender ratio that was almost even, and the participants took 3 IQ tests between childhood and adolescence.
For each APOE4 allele gene an individual carries the participants IQ score was found to drop by 1.91 points. Individuals can only carry two of these genes, but the data suggests that each additional gene multiples the gene’s impairment of IQ: for each gene present the girls scored 3 points lower on testing, while boys scored .33 points lower.
Studies have shown an association between lower childhood IQ with increased biological aging and cardiovascular disease before the age of 65. As published in the journal Neurobiology of Aging, although differences in IQ seem minimal at first consideration, according to the researchers the gene’s impact on cognition is likely to progressively magnify as the carriers continue to age.
“Our results suggest that cognitive differences associated with APOE may emerge early and become magnified later in the life course, and if so, childhood represents a key period of intervention to invest in and boost reserves,” comments lead author Chandra Reynolds in a release.
