Controversial Risk Factors
Alzheimers risk factors
Keep in mind that risk factors are traits or behaviors that may make you statistically more likely than others in the general population to have a certain condition. They are not necessarily "causes" of the condition.
Some research evidence points to the following items as Alzheimer's risk factors, but they remain controversial:
- Low educational level
- Poor linguistic and writing ability
- History of seizures
- Exposure to large amounts of zinc
- Exposure to aluminum
Low educational level
Some research suggests that education is protective. Several studies show that using the mind helps preserve cognition, but it remains unclear whether education relates directly to risk of Alzheimer's disease.
Poor linguistic and writing ability
One highly publicized study suggested that early-life writing samples that show poor grammar and few ideas predispose people to Alzheimer's disease 40 years later. However, this study has been criticized because it involved only a few subjects, and because the criteria for the idea-richness of the writing may have been biased by the researchers' subjectivity.
History of seizures
Seizures are caused by problems in the brain. Because Alzheimer's disease is also affects the brain, researchers have wondered if the two are somehow connected.
Researchers at the Mayo Clinic in Rochester, Minn., compared 145 people suffering various forms of dementia with 290 similar people who were cognitively normal for their age (over 54). Compared with the controls, the people with Alzheimer's were six times more likely to have suffered seizures as adults, and those with other forms of dementia were eight times more likely to have had at least one seizure.
Exposure to large amounts of zinc
Australian researchers have discovered that an unusually large intake of zinc promotes brain changes similar to the neurofibrillary tangles of Alzheimer's disease. The authors based their work on earlier research showing that beta-amyloid peptide, the major ingredient of the senile plaques found in the brain tissue of people with Alzheimer's disease, has a chemical affinity for zinc. Other studies have shown abnormalities of zinc metabolism in early Alzheimer's disease and Down syndrome, a condition that almost always causes Alzheimer's disease if affected individuals live into their 40s or 50s.
The test-tube study showed that beta-amyloid, which is found in soluble form in the normal brain, forms plaque-like clumps at zinc concentrations only slightly higher than those typical of the normal brain.
The authors also mentions two unpublished trials in which people with Alzheimer's disease were given zinc supplements -- and showed apparently accelerated cognitive deterioration.
This study and the research on which it is based do not prove a causal connection between zinc intake and Alzheimer's. But supplement advocate Jonathan Collins, M.D., editor of the newsletter The Townsend Letter for Doctors and Patients advises limiting zinc supplementation to no more than 30 mg a day. Check your supplement label.
Exposure to aluminum
Aluminum is unusually abundant in the neurofibrillary tangles of brain tissue of people with Alzheimer's disease. For years, rumors have circulated that aluminum cookware contributed to the disease. And for just as long, scientists have scoffed at this notion because aluminum is one of the most abundant elements on earth and everyone is exposed to a great deal of it. But at least one study published in the prestigious medical journal Lancet linked an increased risk of Alzheimer's disease to drinking water with more than 11 micrograms of aluminum per liter. If you're concerned enough about aluminum to spend about $100 to have it tested, the National Testing Laboratory of Cleveland includes aluminum in a 74-item test of water quality. Call 800-458-3330, and they'll send you a sampling kit. You return it, and they send you a report.