Genetics may influence your predisposition toward getting Alzheimer’s and they may even be involved in the development of plaques and neurofibrillary tangles. But at the moment, no one knows exactly what causes the brain to deteriorate in the person with Alzheimer’s. Some experts believe that beta-amyloid plaques themselves are the cause of Alzheimer’s Disease, while others point to neurofibrillary tangles as the culprit behind the disease process.
There is also speculation that inflammation may play a role in the development of Alzheimer’s. Inflammation is a normal response by the immune system to injuries and foreign invaders such as cuts, viruses, and disease. Studies have found that middle aged adults with higher than normal levels of C-reactive protein, a substance produced during the inflammatory process, were more likely to develop Alzheimer’s Disease later on. But there is disagreement as to whether inflammation is helpful or harmful to the brain and the destructive processes in Alzheimer’s Disease. Some experts believe inflammation is damaging and ultimately causes the death of neurons. Others believe that the inflammation in Alzheimer’s Disease is actually the body’s attempt to heal itself by combating the buildup of plaque.
Another possible cause may be oxidative stress. Excess production of beta amyloid and inflammation can damage the mitochondria of cells, triggering the overproduction of highly reactive molecules called free radicals. Normal amounts of free radicals can help the body fend off infection. But too many of them can cause damage to the cell structure, which results in tissue breakdown and DNA damage.
Since there is no single cause of Alzheimer’s, it’s important to understand risk factors other than genetic ones that may increase your odds of developing the disease. We already know that a family history of disease raises the odds that you’ll get Alzheimer’s Disease. But just because a family member has Alzheimer’s Disease doesn’t mean you’ll get it. It only means that your chances are higher than the next person who has no relative with Alzheimer’s Disease. Clearly, other factors are also involved.
No doubt about it, the number one risk factor for Alzheimer’s Disease is advancing age. Experts estimate that for every five-year age group over the age of 65, the percentage of people with Alzheimer’s doubles. By the age of 85, your odds of developing Alzheimer’s climbs to 50 percent.
It’s normal to experience a decline in memory and cognitive function as you get older, but not everyone gets Alzheimer’s simply because they age. That’s why scientists know there are other factors at work in the disease process.
Experts have known for years that boxers are prone to memory problems caused by years of fighting in the ring. But research is now starting to uncover a link between head trauma and the development of Alzheimer’s. A study by researchers at the University of Pennsylvania in 2002 found that mild, repetitive head injuries accelerate the onset of Alzheimer’s Disease by increasing free radical damage and the formation of plaque-like deposits of amyloid proteins. Other studies have found a link between head trauma and Parkinson’s disease, another form of dementia. Though scientists have yet to determine how strong the connection is, research strongly suggests that head injuries do raise the risk for developing Alzheimer’s Disease.
Most people know that having high cholesterol and high blood pressure puts them at risk for conditions like cardiovascular disease and diabetes. But recent research is showing that these same risk factors may also play a role in causing Alzheimer’s. These conditions can damage blood vessels, which supply oxygen to the brain, thereby disrupting important neural circuits that we use to perform cognitive functions. Studies done on mice have shown that animals fed diets rich in fat and cholesterol had more beta amyloid plaques in their brain than those eating standard food. And a study by researchers at Columbia University found that a higher intake of fats and calories over time was associated with a greater risk for Alzheimer’s Disease in people carrying the APOE (epsilon) 4 allele.
When the arteries supplying blood to the brain suffers a blockage or a leak, the brain can’t get the oxygen and glucose it needs to function properly. This is known as a stroke. Studies suggest that people who have experienced strokes are more likely to develop symptoms of Alzheimer’s as well as a condition known as vascular dementia. Since the likelihood of having a stroke is influenced by blood pressure and smoking, there is at least a possibility that some people may be able to prevent Alzheimer’s—or minimize its impact—by watching their blood pressure and not smoking, factors that raise the likelihood of a stroke.
Studies on nuns have found some intriguing results that link education with the likelihood of developing Alzheimer’s. Researchers involved in the project, which is known as the Nun Study, examined autobiographical essays that the nuns wrote about themselves at the time they entered the convent. On average, the nuns were 22 years old. The essays were measured for density of ideas—the number of ideas per ten words—and grammatical complexity.
The nuns had all agreed to donate their brains to research upon their deaths. When they died the scientists found that nuns who had earlier written essays rich in ideas had fewer neurofibrillary tangles in their brains. Meanwhile, those whose essays were less idea-rich were more likely to have these tangles.
Subsequent studies have suggested that low levels of education as well as lower socioeconomic status might be associated with Alzheimer’s. Likewise, people who are better educated and who are at the higher tiers of socioeconomic strata may enjoy some protection from Alzheimer’s. Experts believe that somehow the cognitive functioning required of intellectual pursuits may foster more neuronal connections.
However, education obviously cannot protect everyone from Alzheimer’s Disease. Even highly educated people like the writer Iris Murdoch and those with high socioeconomic status like former President Reagan were not able to escape Alzheimer’s grasp.
Studies suggest that women are more likely to develop Alzheimer’s than men. Though the reasons for this are unclear, it may, at least in part, be due to the fact that women outlive men. According to the Centers for Disease Control, women have a life expectancy of about 80 years, while men have a life expectancy of 74 years.
Clearly, these are not the only risk factors for Alzheimer’s. Not everyone who gets Alzheimer’s Disease is poorly educated, female, or elderly. And not everyone has a history of cardiovascular disease, stroke, or head injury. Scientists all around the world are exploring the influence of depression, chemicals, environmental toxins, and cigarette smoking. They’re also examining the impact of lifestyle, especially the foods we eat and the exercise—or lack of it—we do. By pinning down specific risk factors that raise your odds for developing Alzheimer’s Disease, there’s the hope and prospect that the disease might someday, somehow be preventable.
IN THE MEANTIME
If you’ve been told you’re in the early stages of Alzheimer’s or are concerned that you might have Alzheimer’s, you’ve taken an important step toward understanding your condition by reading this book. You’ve set out to learn more about this baffling disease, to understand what it is, why it’s happening to you, and what you can do to take control of the situation. Only by educating yourself are you better able to manage your condition.
So while it’s true that Alzheimer’s is an irreversible, progresssive form of dementia, you may also be surprised to learn that there are factors that can influence the pace at which Alzheimer’s Disease progresses, factors that you can actually control. There are also things you can do to make it easier for you to accept your condition and to live with it more comfortably. ‘
Detecting the disease in its early stage gives you an advantage in many different ways. At this point, you can still actively participate in your choice of medical care and caregiving. You can still make practical decisions about your finances, legal matters, and your living situation. You can still participate in your favorite activities.
No, there is no cure for Alzheimer’s at the time, and having Alzheimer’s Disease is certainly not easy. But learning everything you can about the disease will help you understand the options and possibilities that you have available to you, options that twenty years ago didn’t even exist. Knowledge of Alzheimer’s will also help you live a better life. And that can be most reassuring in the face of an uncertain future.