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Dr. Cyrus Raji is a neuroradioligist specializing in applying multi-modal structural and functional neuroimaging to neuropsychiatric disorders and head trauma.
He has published over 30 peer-reviewed papers on these topics in such journals such as Neurology, Human Brain Mapping, the American Journal of Preventive Medicine, and the American Journal of Neuroradiology.
According to Dr. Raji there are 7 risk factors that account for 50% of the Alzheimer's risk, and if reduced by 10% would result in 1 Million people worldwide not developing Alzheimer's. Here's the paper (written by Dr. Kristine Yaffe)
Here are the risk factors:
According to Dr. Raji's research, once Body Mass Index (BMI) gets over 30, the threshold for obesity, there is a significant reduction in brain volume, specifically in the frontal lobes and hippocampus, areas related to cognitive function.
2. Physical Inactivity
Together, obesity and physical inactivity are the 2 biggest risk factors for cognitive decline inside the US.
Dr. Raji's advice: Move more!
He doesn't care what modality you choose or how intensely you exercise, only that you move frequently. In fact, he urges you to pick the modality that you enjoy as you're more likely to be consistent with that one.
Dr. Raji reminds us that exercise is linked to increased BDNF, aka "Miracle-Gro" for your brain, a growth factor that can help provide the signal and scaffolding" as Dr. Raji describes it, to help grown new neural cells.
You shouldn't need me to tell you that smoking is harmful to your health.
If you want data, the Alzheimer's Drug Discovery Foundation says cigarettes contain up to 4,700 chemical compounds that can be harmful to our brains and cessation of smoking can reduce Alzheimer's risk by up to 79%.
Higher education levels are linked to decreased risk of Alzheimer's Disease.
It's not just Dr. Raji who has connected education levels and Alzheimer's links. A quick search on Pub Med or Google Scholar will bring back a slew of studies like this one.
According to researchers, "Life experiences that engage the brain, such as higher educational attainment in this case, may protect against biological changes in the brain that underlie Alzheimer’s."
Low education is the biggest risk factor for cognitive decline outside of the US.
Diabetes is a risk factor for Alzheimer's in it's own right. While it may sound related to obesity and physical inactivity, complications from this dysfunction can increase risk of Alzheimer's
In his research Dr. Raji has separated obesity and physical inactivity from diabetes. Those with with diabetes who are not obese have a lower risk than those who are obese - but there remains an elevated risk compared to those without diabetes.
In fact the link between Type 2 diabetes and Alzheimer's is growing so strong that this 2015 paper in Neurology argues that Alzheimer's "may actually be the late stages of type 2 diabetes."
6. Blood Pressure (at mid-life)
Specifically, Dr. Raji highlights early and mid-life abnormalities in blood pressure as greater risk factors than elevated blood pressure later in life.
The link between depression and Alzheimer's in an interesting one. Listen to the podcast below to hear Dr. Raji discuss the structural and functional similarities - and differences - in brain scans for patients with these conditions.
What does it mean
There is good news. As Dr. Raji says, a 10% reduction in these risk factors has massive impact - a reduction of more than 1 million people being impacted by this cruel disease.
Even better news is that these risk factors are within our control and completely modifiable with lifestyle.
Listen to the entire interview:
Links and Resources
Dr. Raji's lecture on Brain Health and Imaging at the Silicon Valley Health Institute