as discussed above, some biomedical researchers argue this number is a low estimate. They instead suggest there are currently 50 million people worldwide suffering from the disease. This number is expected to increase almost four-and-a-half times by the middle of the century. By that time, using the conservative guesstimate, approximately 120 million people around the world will be diagnosed with Alzheimer’s disease.
In Canada, the number of cases of Alzheimer’s disease is projected to more than double within the next 25 years. At present over half a million Canadians suffer from Alzheimer’s. More than 71,000 sufferers are younger than 65 years of age. Things don’t look good for the future because currently a new case of is diagnosed every five minutes. Within 25 years or so, that number is expected to increase with a case of Alzheimer’s disease being diagnosed every two minutes. Similar numbers have been reported for other countries. For example, currently in Australia there are approximately 270,000 people suffering from Alzheimer’s disease. This number is projected to reach one million by 2050.
If you think about those numbers, it will immediately become clear that not only are the implications to the individual devastating but the significance to society is equally compelling. The increasing cost to healthcare alone is almost incomprehensible.
Different Countries, Different Problems
But there is another aspect to the increasing Alzheimer’s epidemic. Less-well-off countries are going to pay a higher price because the number of people with the disease will be greater in those countries. Data have revealed that the development of Alzheimer’s disease is directly linked to economics. Individuals from poorer countries are more likely to suffer from it than those from well-off countries. The data presented in Figure 2.4 summarize this information. As time passes, about five times more individuals will develop Alzheimer’s in low- to middle-income countries compared to those in better-off countries.
Figure 2.3. The number of individuals with Alzheimer’s disease varies based on the country’s income. (Modified from: Wortman and Wimo, 2011)
What does this mean economically? Well, it’s estimated that the current cost of Alzheimer’s disease worldwide is over $600 billion US per year. Or, as an economist might write it: at present Alzheimer’s costs us 1% of the global gross domestic product. And things are predicted to get worse. To be blunt, the cost of the disease in the US alone is projected to be in the hundreds of billions of dollars annually. Internationally the economic burden of the disease is projected at somewhere around $15 billion. Within one generation this number is expected to balloon tenfold to about $150 billion annually. While one might argue about the exact costs, there is no doubt the international economic impact of Alzheimer’s will be staggering if the current situation persists. Thankfully, some countries have begun to develop action plans in the fight against the Alzheimer’s epidemic.
Developing an Action Plan
While only a limited number of governments have begun to develop action plans to deal with the Alzheimer’s epidemic in their country, the results of their work will help guide other governments in the future. While the action plans of those countries that have implemented them do vary, overall these plans are designed to raise awareness, improve education, improve care and garner more money for research into the disease. Research funding would go towards the search for “cures” and early diagnosis, among other things that will be detailed later. Several countries initiated Alzheimer’s disease action plans during the first decade of this century. The countries showing this foresight include Australia, Denmark, England, France, Korea, the Netherlands, Norway and Sweden, among others. For example in 2008, President Sarkozy implemented the third “French Alzheimer Plan” at a cost of 1.6 billion Euros. The success of this plan was validated three years later in 2011, leading to another three-year plan being implemented. Others, such as the US and many European countries, have plans under development. In contrast, some countries such as Canada did not have a national strategy at the time this book was written. In spite of the initiatives taken by many countries, most still are ill prepared to face the reality of the Alzheimer’s epidemic. Later in the book, we’ll discuss what is and what can be done to reduce these numbers and costs.
Chapter 3
The Stages of Alzheimer’s Disease
There are a multitude of reasons why it is critical to precisely determine the stages in the progression of Alzheimer’s disease. For family members, it’s essential to accept the severity of the disease so that they can make decisions about whether home care is sufficient or whether their parent or grandparent should move into a long-term care residence. For the family physician, knowledge about the status of the patient can guide him or her in suggesting the appropriate therapy. For researchers, defining the exact stage of progress of the disease is paramount. Only when the stages of Alzheimer’s are well defined can effective and meaningful research be done.
Historically, much of the work to date on the disease has simply led to developing more meaningful and appropriate staging criteria. But even today, Alzheimer’s research groups are fine-tuning their definitions not only of the stages but also of the specific changes that occur at each stage. As more clinical indicators of the disease are discovered, it may one day be possible to determine exactly when the disease starts. One thing we do know is that the symptoms of Alzheimer’s don’t appear until long after the disease has been set in motion.
The Onset and Progression of Alzheimer’s Disease
Since Alzheimer’s disease starts long before there are any overt symptoms, this makes the search for causes and a cure much more difficult. Figure 3.1 provides a simple summary of how the as yet undetermined initiating events precede the presymptomatic phase. As its name implies, a person shows no symptoms during the presymptomatic phase. The presymptomatic phase is followed some time later by the actual symptoms of the disease where initially observed cognitive deficiencies often progress over time. As we will learn, there are some known predictors of Alzheimer’s disease. There are certain genes that are linked to the disease, for example, but the actual initiating events that drive the onset of the disease are not known.
Figure 3.1. The onset and progression of Alzheimer’s disease.
So, after the ground has been laid for the disease, it is followed by a long presymptomatic phase where the person appears completely normal and exhibits no cognitive deficiencies. Their memory is good, they recognize friends, family and items; they relate to the world around themselves. But during this time changes in the brain are occurring which will alter how their brain cells talk to each other. This progressive failure in brain cell communication underlies the events that will define the symptomatic phase, because without normal brain cell intercommunication, cognitive deficiencies become evident which usually can progress to greater brain malfunction.
The goal of biomedical research, and the underlying focus of this volume, is to study the progression of Alzheimer’s disease from the events that initiate it through to the final changes that face individuals who develop full-blown dementia. As summarized in Figure 3.2., by asking and answering specific questions at each stage, not only can the disease be better understood but new therapies can be developed. For example, by answering the question, “How does the disease start?” researchers will ultimately answer the question of how to cure the disease. The value will be the ability to stop the disease before it starts. This, of course, is the most challenging issue. After all, how can you study something that apparently hasn’t happened yet?
Knowing
