Nearly 15 million people in the United States take care of a loved one with Alzheimer’s disease or another form of dementia, amounting to 17 billion hours or more than $202 billion in unpaid care, Alzheimer’s experts said on Tuesday.

If these caregivers all lived in one U.S. state, it would be the nation’s fifth largest, according to the Alzheimer’s Association’s 2011 annual report on the disease.

The report illustrates the growing burden of Alzheimer’s disease, a fatal brain-wasting disease that erodes memory, thinking, behavior and the ability to handle daily activities.

Alzheimer’s affects more than 26 million people globally and can stretch on for years, slowly robbing patients of their mind and memories. And there are currently no drugs that can keep the disease from progressing.

“Alzheimer’s disease doesn’t just affect those with it. It invades families and the lives of everyone around them,” Harry Johns, president and chief executive of the Alzheimer’s Association, said in a statement.

The new report shows a 37 percent increase in Alzheimer’s and dementia caregivers compared with a year ago, but much of that increase is because the year-ago figure had been based on nine-year-old estimates, Beth Kallmyer of the Alzheimer’s Association said in a telephone interview.

Even so, the number of unpaid caregivers is staggering, Bill Thies, the association’s chief medical and scientific officer said in a telephone interview.

‘ONLY GOING TO GET WORSE’

“We are in the early stages of an epidemic and it is only going to get worse over the next four years, and these costs are going to continue to grow,” Thies said.

The group estimates that 5.4 million people in the United States are now living with Alzheimer’s disease, up from 5.3 million a year ago. That includes 5.2 million people over age 65 or about one in eight senior citizens.

A 65-year-old person diagnosed with Alzheimer’s typically lives four to eight years after being diagnosed, but some patients live as long as 20 years after diagnosis.

That takes an emotional toll, Kallmyer said.

“It’s hard to take care of somebody that you love who doesn’t remember who you are.”

Kallmyer said more than 60 percent of caregivers say they are stressed, and more than a third say they are depressed.

Treating the disease is expensive.