May 21, 2020
In a nationally representative sample of older US military veterans, the negative effect of depression on cognitive functioning was moderated by a pair of factors that affect brain-derived neurotropic factor (BDNF) function in the brain: BDNF Val66Met genotype and physical exercise. Researchers published their findings online in The American Journal of Geriatric Psychiatry.
“Depression is associated with increased risk for cognitive dysfunction,” researchers wrote, “yet little is known about genetic and behavioral factors that may moderate this association.”
The study looked at the effects of depression, BDNF Val66Met genotype, and physical exercise on cognitive functioning in 1386 European-American veterans whose average age was 63.
On the whole, veterans with depression scored worse than veterans without depression in both subjective measures of cognitive functioning and objective measures of visual learning and working memory, according to the study. Among veterans with depression, Met allele carriers scored worse than Val/Val homozygotes on subjective cognitive measures and an objective measure of visual learning.
Physical exercise, however, moderated the link between depression and cognitive function, researchers found. Veterans with depression who exercised had better scores than those who did not exercise on a subjective reasoning measure as well as objective measures of processing speed, attention, and visual learning. In veterans with depression who were Met allele carriers, those who exercised had better scores than those who did not on subjective cognitive and objective visual learning and working memory tasks.
“Prevention and treatment efforts designed to promote physical exercise may help preserve cognitive functioning in at-risk veterans,” researchers concluded.
Pitts BL, Wen V, Whealin JM, et al. Depression and Cognitive Dysfunction in Older U.S. Military Veterans: Moderating Effects of BDNF Val66Met Polymorphism and Physical Exercise [published online ahead of print, 2020 Feb 7]. Am J Geriatr Psychiatry. 2020;S1064-7481(20)30217-7. doi:10.1016/j.jagp.2020.02.001