A new study conducted by researchers at Johns Hopkins University School of Medicine reveals a growing number of vascular risk factors, including hypertension, diabetes mellitus, hyperlipidemia (high cholesterol), smoking and obesity cause the amyloid levels in the brain to increase. Amyloid, a collection of abnormal proteins that form insoluble fibers in organs and tissues, are linked to Alzheimer’s disease.
While midlife vascular risk factors are linked to dementia, it is not clear whether they are directly connected to amyloid deposition in the brain. The team of researcher examined data of 346 individuals, who were all dementia-free, evaluating markers and vascular risk factors. All of the participants had undergone previous PET scans as part of the Atherosclerosis Risk in Communities (ARIC) and 2012-2013 Pet Amyloid Imaging Trials.
When the ARIC study was completed, the participants were between the ages of 45 and 64. The risk factors included current smoking, diabetes, body mass index (BMI) 30 or greater and total cholesterol of 200 mg/dL or higher. A number of models were also evaluated, including gender, age, race, educational level and APOE genotype.
Brain amyloid, potential biomarkers, allow for early detection of dementia, as well as provide insights into the role of vascular disease to amyloid deposition and cognition.
The findings reveal an accumulated number of midlife vascular risk factors are linked to increased brain amyloid regardless of race, despite the fact that later-life vascular risk factors are not connected to later-life brain amyloid deposition. The findings are not remarkable among people, who do not carry or carry the Apolipoprotein E (APOE) ε4 allele, the risk factor gene that increases the risk for developing late-onset Alzheimer’s.
The authors noted, “These data support the concept that midlife, but not late-life exposure to these vascular risk factors is important for amyloid deposition… These findings are consistent for a role of vascular disease in the development of AD.”
The findings were published in the Journal of the American Medical Association (JAMA).