The cost of forgetting

Researchers race to find a solution to an impending Alzheimer's epidemic

People often say that forgetting with age is normal, but in fact, it can be much more serious. Not being able to remember where you put your keys in the house is fine. However, not remembering what car keys are used for is a different matter. Such cognitive malfunction is a symptom of Alzheimer’s disease, the most common form of dementia. It is a progressive, degenerative, and fatal brain disease that causes memory loss, cognitive disabilities, and eventually even removes the ability to carry out simple tasks. Currently, there is no cure.

According to the Alzheimer’s Society of Canada, approximately 500,000 Canadians have dementia today. It is the most significant cause of disability among Canadians over the age of 65. Health care costs come to about $15 billion a year, including direct health costs, unpaid caregiver opportunity costs, and indirect costs according to the Fédération québécoise des sociétés Alzheimer.

Alarmingly, forecasts show that within twenty years, worldwide prevalence will increase two-fold. This increase is due to the “baby boomer” generation born after the end of World War II, who are now reaching the age of sixty to 65 – the age range of Alzheimer’s onset. With the wave of an increasingly older population, the number of patients is estimated to rise almost exponentially in the next fifty years, carrying with it tremendous expenses. In fact, the total economic burden is expected to reach $872 billion in thirty years (in 2008 dollars).

While many new medications are being developed for mental illness, no drug has been approved for Alzheimer’s in the past seven years. It is more a question of methodology than a lack of investment in the area. Alzheimer’s is not found in dogs, mice, rats, cats, or even monkeys. Without animal models to study the disease – without subjects to recreate aspects of the disease and test cures – it’s much more difficult to generate new drugs. The only way is to work with humans and try to understand the physiology of the brains of those who have died from the disease. However, this is insufficient for identifying the its causes, since Alzheimer’s can only show at its end, not its progression.

Currently, many researchers at the McGill Centre for Studies in Aging (MCSA) are working on this neurodegenerative disease. In 1993, Judes Poirier, Professor of Medicine and Psychiatry at McGill and Senior Scientist of the Canadian Institute for Aging Research, identified the protein Apolipoprotein E (APOE), a significant indicator of Alzheimer’s, found in fifty to sixty per cent of all Alzheimer’s patients. Transgenic APOE animals (animals into which the human gene was inserted) show typical features of the disease, such as memory deficit, deoxidation of brain cells and disconnection of the synapses.

Poirier and colleagues are attempting to use the protein as a target for treatment. “We know that if we are capable of pushing the onset of the disease by five years, in one generation – fifty years – there’s going to be fifty per cent less people with Alzheimer’s disease,” said Poirier. “Just by pushing it by five years, half of those people will die of old age, not Alzheimer’s disease. If we push the disease by ten years, then it’s 95 per cent of Alzheimer’s disease that will disappear. So we actually don’t have to cure the disease. We simply have to push it in the future by five to ten years. And by ten years, we have almost eliminated the disease,” Poirier said.

At McGill’s own Douglas Hospital Research Centre (DHRC), the first Canadian centre for the prevention of Alzheimer’s disease will be established. “We’re now going to start to work, not when the disease is there, but years before where there are actually symptoms. And we’re trying to understand the biology just before the arrival of the disease.”

A study at the Karolinska Institute in Stockholm has helped determine the respective effects of genetics and environment in the development of Alzheimer’s. Based on a sample of 11,000 identical twins, findings show that 75 per cent of twins with a brother or sister with the disease will eventually also develop Alzheimer’s. Accordingly, the genetic component in determining an onset is 75 per cent. Environmental factors compose the remaining 25 per cent.

The environment component consists of several factors. First, anti-inflammatory drugs appear to reduce the risk of having Alzheimer’s, particularly in an older population sample that has no memory deficit or other symptoms to begin with. Diet and nutrition is also an important aspect. Diets rich in omega-3, consisting heavily of fruits and vegetables – the diet also believed to lower heart disease – have now been shown in Alzheimer’s prevention studies to have an impact on the onset of the disease. Exercise, again important for prevention of heart disease, is the third factor. As hypertension, cholesterol levels, and blood sugar levels are controlled, the risk for Alzheimer’s falls, along with the risk of heart disease. What’s good for the heart is also good for the brain.

In 2004, the Canadian government conducted a study on Alzheimer’s disease across the country. They discovered that of all Alzheimer’s cases, only 19 per cent were diagnosed and treated with the existing medications. Eleven per cent of Alzheimer’s patients were diagnosed, but not treated. According to Poirier, some doctors didn’t – and still don’t – believe the drugs were effective enough and did not prescribe any medication. The remaining seventy per cent were not diagnosed, nor treated. As there is no cure, these medications only decrease the speed of memory loss. These drugs aid memory retention for only one to two years. The earlier the disease is recognized however, the better and longer the medication will work.

“There are currently four drugs out in the market that will help memory in Alzheimer’s patients,” explained Poirier, referring to the medications Ebixa, Aricept, Exelon, and Reminyl. “Now we believe we’ve gone from seventy per cent [of cases] not diagnosed nor treated to about forty to 45 per cent. There are still some doctors who don’t want to bother with the treatment of Alzheimer’s disease. They don’t believe in the science or they find it too complicated, annoying, or they just don’t care. We still have to educate our doctors to recognize it and do something about it. We also have to sensitize the families to be more active, to react, and not assume it’s just old age.”

The Quebec government in particular has been active in helping Alzheimer’s patients as well as caregivers. The province pays for the first medication taken, and also sends nurses to aid patients. Local Alzheimer’s societies also exist throughout Quebec. However, the care infrastructure is not yet perfect.

“We’re still short of long-term care facilities,” Poirier pointed out. “There’s a point where the caregivers can do something but there’s also a point where it’s so exhausting for them. And then [the government] has to start treating the caregiver. So when it gets that difficult, we need specialized institutions, like a long-term caregiver home. And there are so few of them that we just can’t match what’s needed.”