Here are two evils — Alzheimer’s disease and cancer. Which would you choose? Of course, neither. I recently read something that said if you have Alzheimer’s you’re not likely to get cancer and vice versa, if you get cancer, you’re not likely to get Alzheimer’s. So that got me researching — is Alzheimer’s disease protection for cancer?

In December 2009, Neurology published a report by Dr. Catherine M. Roe of Washington University School of Medicine in St. Louis which stated that understanding the link between Alzheimer’s disease and cancer may lead to possible treatments.

Roe and her team studied 3,020 people aged 65 and older. They were followed for an average of five years to see if they developed dementia and an average of eight years for cancer. Here is how the study started:

• 164 (5.4%) had Alzheimer’s disease
• 522 (17.3%) had cancer

Here is what they found:

For people who had Alzheimer’s disease at the outset, the risk of future cancer was reduced by 69 percent compared to those who did not have Alzheimer’s disease when the study started.

For white people who had cancer when the study started, their risk of developing Alzheimer’s disease was reduced by 43 percent compared to people who did not have cancer at the start of the study.

This effect, however, did not apply to minority populations. In fact, the opposite effect was observed in minority populations — those who started out with cancer at the beginning of the study were more likely to develop Alzheimer’s disease. However, the sample size of minorities starting off with cancer (29 individuals) was too small for the result to be considered significant.

Overall, the results of this study support previous findings that cancer and brain degenerative diseases such as Parkinson’s and Alzheimer’s disease may share common molecular underpinnings. However, Roe noted in an email to Reuters Health, “Since we found no associations between vascular dementia and cancer, we don’t think that cancer is linked to dementia generally.”

Vascular dementia, the second most common form of dementia after Alzheimer’s disease, is caused by clogged blood vessels and other conditions affecting the blood supply to the brain. Based on the current study, only the degenerative form of dementia, and not the form caused by lack of blood to the brain, appears to be somehow protective against cancer.

To read the full article, click here.

Brain Tour from Alzheimer's Association (click image)

Just what is Alzheimer’s disease (AD)? Everyone seems to agree that it is the most common form of dementia accounting for at least half of all dementia cases. (See previous post on discussion of dementia). There is also agreement that in advanced Alzheimer’s disease, a person cannot function intellectually and socially. According to the Mayo Clinic, “Alzheimer’s disease is not a part of normal aging, but the risk of the disorder increases with age. About 5 percent of people between the ages of 65 and 74 have Alzheimer’s disease, while nearly half the people over the age of 85 have Alzheimer’s.”

What is happening in the brain that is causing a person not to be able to function intellectually and socially? Take the “Brain Tour” on the left and notice the shrinkage of the brain as well as the tangles. Just looking at those pictures explains the confusion, doesn’t it?

According to the Mayo Clinic, there are currently three major areas that doctors depend on to make a diagnosis:

1. Lab tests
2. Neuropsychological testing (extensive assessment of thinking and memory skills)
3. Brain scans
   • Magnetic resonance imaging (MRI)
   • Computerized tomography (CT)
   • Positron emission tomography (PET)

Although memory assessments should always be conducted by a medical practitioner, here are two quick paper and pencil tests. The first was published by Times Online (UK) called the “Five Minute Alzheimer’s Test.” The second one is on the Web site of a well-known Alzheimer’s drug, but it states, “This screening tool cannot be used to tell if your loved one has a medical problem, only whether he or she should be tested.” It was adapted from Galvin JE, et al. The AD8, a brief informant interview to detect dementia. Neurology 2005:65:559-564.

Once again, do not draw any conclusions from these memory tests. As discussed by Carrie Hill, Ph.D. in “What you Need to Know about Screenings for Memory Problems,” she states:

1. A memory screening should not be used to make a diagnosis
2. A memory screening does not replace a diagnostic workup
3. Memory screenings should only be performed by qualified professionals
4. Memory screenings should be confidential and provide follow-up resources
5. Memory screenings can be used to establish a baseline
6. Opinions differ on the value of memory screenings. Here she talks about the different views of the two leading non-profit Alzheimer’s organizations — Alzheimer’s Foundation of America and Alzheimer’s Association.

In our next blog post next week, we will look at the most recent diagnosis tools. In the meantime, have you done your Sudoku for today?