Alzheimer’s Disease and Polio Survivors
Question: Is it true most polio victims do not get Alzheimer's? I read that it has something to do with our chromosomes.
Dr. Bruno’s Response: Well, we can’t say "most" don't get Alzheimer's. But one study showed polio survivors had 12 times less Alzheimer's disease than those who didn't have polio:
From The Polio Paradox . . .
“Polio: a Good, Bad Thing? I may sound like Pollyanna, but there may actually be benefits to having gotten polio, or at least a benefit to being susceptible to it. Biology graduate student Shanda Davis surveyed polio survivors and the alumni of Drew University, asking if they had been diagnosed with Alzheimer's disease. Remarkably, 3.6% of the Drew Alumni had Alzheimer's but only 0.3% of the polio survivors did. Polio survivors had 12 times less Alzheimer's disease than those who didn't have polio. I bet you're thinking this must be a mistake. But we went back to our own patients and found that only 0.4% of the polio survivors who have ever been evaluated at The Post-Polio Institute had Alzheimer's disease. If these percentages are correct how could having had polio protect you from getting Alzheimer's disease? Shanda Davis had a hunch. We discussed that the gene which makes the poliovirus receptor is found on chromosome 19. Well the poliovirus receptor gene shares its DNA on chromosome 19 with a gene that makes another protein, called APOE-4, a protein that has been is associated with getting Alzheimer's disease. You can inherit one APOE-4 gene from each parent. Those who get two APOE-4 genes have the highest risk for Alzheimer's. Those who only inherit one APOE-4 gene have a lesser risk, while those who inherit no APOE-4 genes have the lowest risk of all. Without an APOE-4 gene on chromosome 19, the poliovirus receptor gene doesn't have to share any of its DNA and may be more able to make poliovirus receptors. Without the APOE-4 you would be more likely to have more poliovirus receptors and to get polio as a child, but be less likely to get Alzheimer's disease as an adult. Maybe even the dark cloud of polio has a silver lining.”