A new study out of the University of California's Davis School of Medicine is claiming that signs of cognitive decline, which can potentially lead to Alzheimer's disease, can be detected in the brain at a much earlier age than previously believed.

For this study, the researchers examined nearly 1,900 participants from the Framingham Heart Study. All of the participants had undergone brain magnetic resonance imaging (MRI) and an arterial tonometry, which is a non-invasive test that can measure carotid femoral pulse wave velocity (CFPWV), an indicator of aortic stiffness. Both tests also recorded the force of blood flow in the arteries and CFPWV in relation to any evidence of injury in the brain's white and gray matter.

The researchers found that in healthy adults who were in their 40s, having a greater degree of aortic stiffness was associated with reduced white matter volume and a decline in grey matter integrity in the brain. The researchers reported that increased CFPWV was tied to having more injuries in the brain.

"This study shows for the first time that increasing arterial stiffness is detrimental to the brain, and that increasing stiffness and brain injury begin in early middle life, before we commonly think of prevalent diseases such as atherosclerosis, coronary artery disease or stroke having an impact," said Pauline Maillard at UC Davis Department of Neurology and Center for Neuroscience. "These results may be a new avenue of treatment to sustain brain health."

Despite the study's findings, the researchers could not explain why arterial stiffness was associated with greater brain atrophy. They reasoned that since arterial stiffness can be caused by high blood pressure, having the medical condition could be contributing negatively to brain health. The researchers explained that increasing blood pressure levels mixed with a greater amount of calcium and collagen deposits can cause the arteries to stiffen even more. When further stiffening is combined with inflammation, caused by the deposits, blood flow to the brain can be reduced, which can potentially cause brain injury.

"Our results emphasize the need for primary and secondary prevention of vascular stiffness and remodeling as a way to protect brain health," Maillard said.

The study was published in the American Heart Association's journal, Stroke.