The study, published in Biological Psychiatry, examined the interactive relationship between a variant of a gene that contributes to the risk for memory loss related to Alzheimer's disease and high circulating levels of cortisol -- associated with high stress levels that also impairs memory.

"The results of the study have implications for interventions that could prevent harmful responses to stressful experiences, and, as a result, could prevent or slow the progression of cognitive changes in genetically vulnerable, older individuals," one of the study authors Guerry M. Peavy of the University of California in San Diego said in a statement.

In the study, the researchers performed genotyping and measured the chronic stress level in 91 healthy subjects. The mean age was 78.8 years. Those low on stress or without the genetic risk factor performed better on memory measures than those with high stress or those positive for the gene variant, respectively. Those individuals experiencing high stress and who were positive for the gene variant showed the greatest memory impairment.