Tuesday, January 27, 2009

Dementia in Canada

Who has dementia?

According to the government: 1 in 11 of Canada’s seniors has Alzheimer’s disease or a related dementia. What is more frightening are those who are undiagnosed, driving and alone in their homes.

What Is Dementia?
To be diagnosed with dementia means that one has a progressive and irreversible loss of cognitive ability. With the progression of dementia, brain cells are unable to process information and mental abilities begin to diminish.

Symptoms include memory loss (short, and long term), confusion, and inappropriate social interactions. It is the fourth leading cause of death in Canada. Although it is underdiagnosed as a cause of death.

What Causes Dementia?

* Vascular dementia - the brain cells do not receive enough blood supply and oxygen
* Alzheimer's disease
* Parkinson's disease
* AIDS dementia

Alzheimer's accounts for more than half of all dementia, but as many as 50 different disorders can cause dementia. Many can be treated by addressing the underlying condition. In addition, other cardiovascular issues can cause the symptoms.

Strokes -- Diseases that affect blood vessels in the brain, such as high blood pressure or cardiovascular disease, can cause vascular dementia, usually from multiple small strokes. Controlling high blood pressure, stopping smoking, reducing cholesterol levels and treating cardiovascular disease and diabetes can lessen vascular dementia, but not eradicate it.

Infections -- HIV and AIDS, tuberculosis, syphilis and certain types of meningitis and encephalitis can cause inflammation in your brain, resulting in damage to nerve cells.

Medications -- The most common drugs that can cause temporary mental impairment are sedatives, sleep medications and tricyclic antidepressants. But rarely, even some antibiotics can produce temporary symptoms of dementia.

Brain injuries and abnormalities -- A serious head injury, even one that happened years earlier, can cause dementia. Brain tumors can also cause dementia.

Other causes -- Inadequate thyroid hormone (hypothyroidism), vitamin B12 deficiency, depression and alcohol abuse can also cause a decline in brain function resembling dementia.

What Are the Most Common Symptoms of Dementia?

* confusion
* forgetfulness
* agitation and anger, swearing
* sitting doing nothing
* repeating themselves
* stubbornness
* sleep disturbance
* suspicious of others

How Widespread Is Dementia?
Alzheimer's is the fourth most common cause of death in Canada's seniors after cancer, heart disease and stroke. In 1991, 8 per cent of the Canadian population 65+ suffered from dementia and it is expected that the number of Canadians with dementia will triple between 1991 and 2031, whereas the population 65+ will double in this time period. In 1991, of those Canadian seniors suffering from dementia, 18 per cent were 65-74 (44,700 seniors); 44 per cent were 75-84 (110,200 seniors); 39 per cent were 85+ (97,700 seniors).

It is estimated that dementia is present in:

* 23% of seniors aged 85-89
* 40% of seniors aged 90-94
* 55% of seniors aged 95-99
* 85% of seniors aged 100-106

The number of dementia cases (present and projected) in Canada:

* 2001 364,000
* 2011 475,000
* 2021 592,000
* 2031 778,000

According to Dr. Robert Hopkins of the Psychogeriatric Unit at Kingston Psychiatric Hospital, who has released dementia projections for the counties, regional municipalities and districts of Ontario, the elderly portion of the population in Ontario (i.e. those aged 65 and over) will increase greatly in the near future, approximately 22 per cent in five years, 58% in 15 years and nearly 120% in 25 years (i.e. in 2021). This will lead to a great increase in all age-related disorders.

A second observation is that the prevalence of dementia is increasing even more rapidly. By 2001, the number of moderate to severe cases of dementia will increase by nearly a third over 1992 levels. This increase is caused by the fact that the oldest age categories (i.e. 85-89 and 90+) will be expanding greatly from present levels and have extremely high rates of dementia.

What Is the Risk That You Will Develop Dementia?
If you have a close relative with Alzheimer's, your chances of developing the disease are increased by 2.5 times. The risk of developing Alzheimer's is higher if you have had a previous head injury or have worked in a job that has exposed you to glue, pesticides and fertilizers. According to the researchers at the Tanz Institute, the disease is also more prevalent in those with less education -- if you haven't completed grade seven (they aren't sure why). There is little evidence linking the use of products containing aluminum and the risk of developing Alzheimer's.

What Are the Mortality Rates?
In Canada 10,000 deaths per year can be directly attributed to dementia. As many as 100,000-300,000 deaths may be caused by dementia to a varying degree (1985 data).

The approximate life expectancy of an Alzheimer sufferer is eight years from the onset of symptoms; however, some people have survived for 20+ years after that. People with vascular dementia, overall, have fewer years of life remaining after diagnosis than those with Alzheimer's.

What About Tests to Predict the Onset of Dementia?
There are no absolutely accurate tests for dementia, only susceptibility factors. However, some cognitive testing studies being done at Sunnybrook Health Science Centre indicate that cognitive tests are the best way at present to predict AD. Test results showed that the cognitive tests predicted who would develop AD with an accuracy rate of about 90 per cent. Choosing the right cognitive tests is very important, according to Dr. Mary Tierney who conducted the study. Her studies showed that using two particular tests together had the best results: a delayed recall test that examined the person's ability to learn new things and recall them after a short delay and a mental control test that looked at the person's ability to concentrate on how to solve a problem quickly.

What About Genetic Testing?
Genetic testing for the apolipoprotein E-4 gene (apo E-4) was not as successful as the cognitive tests, according to another study by Dr. Tierney. The accuracy rate of apo E-4 for predicting AD was only about 74 per cent.

To ensure the reliability of cognitive tests, they must be conducted by experts. Patients need to ask their family doctor for referrals to hospital psychologists who specialize in geriatric cognitive testing. The test usually take about 20 minutes.

Those who are likely to get AD can plan for it and watch for symptoms.
(*Information from National Advisory Council on Aging, 1996)

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