A new study suggests 71,000, or roughly 15 per cent of the half-million Canadians living with Alzheimer's or other forms of related dementia, are under the age of 65.

And about 50,000 of those are 59 or younger.

The numbers, released by the Alzheimer Society of Canada, suggest an increasing number of younger Canadians are being struck by the disease, typically seen as afflicting the elderly.

According to a projection in the study, an additional 250,000 Canadians could develop Alzheimer's or related dementia, within just five years.

Within 25 years, the number of afflicted Canadians could climb to between 1 million and 1.3 million, the study predicts.

"If nothing changes, I think it is safe to say the system will be overwhelmed," Scott Dudgeon, CEO of the Alzheimer Society of Canada, told CTV News.

The numbers were released Monday in conjunction with Alzheimer Awareness Month.

The study also found that one in 11 people over the age of 65 currently have Alzheimer's or other related forms of dementia.

Of the total number of Canadians with Alzheimer's, women make up 72 per cent.

Ray Congdon, volunteer president of the Alzheimer Society of Canada, said the number of Canadians living with the disease, or related dementia, could double within a generation.

"This new data only reinforces the fact that Alzheimer's disease and related dementias are a rising concern in this country, an epidemic that has the potential to overwhelm the Canadian health care system if changes are not made today," he said.

There is no cure for Alzheimer's or other forms of dementia, which are characterized by a number of symptoms that can include memory loss, impaired judgement or reasoning, as well as changes in behaviours and mood. Dementia can also inhibit a patient's ability to perform daily tasks.

As the disease progresses, the strain grows on families and caregivers and patients eventually need round-the-clock care.

The society is calling on Canadians to take action, by making a donation to research initiatives, lobbying their MPs, and reducing the risk of dementia in their own lives.

"Every Canadian has a reason to care," said Jim Mann, an Alzheimer advocate who was diagnosed with the disease at the age of 58.

"Alzheimer's disease and related dementias are a tragic reality for a rapidly growing number of Canadian families. The time to act is now."

Dr. Bob Lester, retired from Toronto's Sunnybrook Health Sciences Centres, is caring for his wife Judy, who began showing signs of dementia when she was in her 50's. The avid tennis player who had a thriving therapist's practice was formally diagnosed at the age of 62. At 69, she needs full-time care, at a cost of $60,000 per year.

On CTV's health blog, Lester writes of the pain of watching his wife of 48 years slowly being taken from him.

"It's a loss of everything," he told CTV News. "Your hopes, your dreams."

With a report from medical specialist Avis Favaro and producer Elizabeth St. Philip