Alzheimer's disease will claim about one in eight baby boomers in their lifetime, or about 10 million Americans, a new report suggests.

Medicare spending for Alzheimer's will jump to $38 billion in 2025, when those born between 1946 and 1964 start to reach the median age for nursing home admission, according to the Chicago-based Alzheimer's Association. That compares with a Medicare outlay of about $21 billion in 2005, the group said.

Unless new treatments are developed, the time and out-of- pocket costs for family caregivers will increase as well, the group said. Karen Holland, whose husband Edward doesn't always remember who she is, said she knows how confusing it's been for him, and difficult for her. Holland, born in 1947, says her fellow baby boomers aren't ready for what's coming.

"I think that in baby boomers, there's a lot of denial," said Holland, who works at the association's New York City chapter. "It's the same problem with people not wanting to do wills because you don't want to think about that."

Holland and others say more research is needed on the condition, and that families should prepare themselves better as her generation gets older. The report said 7.7 million people will have Alzheimer's by 2030, a 48 percent rise from 2008, and lists the prevalence of the disease by state, the number of caregivers, the hours of unpaid work watching patients and the costs of health care for Alzheimer's patients.

By 2010, Alaska and Colorado will record a 47 percent rise in cases from 2000, the biggest jump among states, the report said. Wyoming is next with a 43 percent rise.

In 2007, some 10 million caregivers like Karen Holland provided free care for someone with Alzheimer's. The value of that care is estimated at $89 billion, according to the report. Patients with Alzheimer's and other dementias cost Medicare almost three times more than patients without, for an average cost of $13,207 per patient in 2000.

Karen Holland's husband, Edward, 76, has been in a nursing home for two and a half years, after episodes in which he thought his wife was trying to kill him.

The first symptom of Alzheimer's may be mild forgetfulness. As the condition progresses, it begins to interfere with patients' lives as they forget how to brush their teeth, change their clothes, or recognize once-familiar people. They become confused and agitated and eventually require constant care, according to the Bethesda, Maryland-based National Institute on Aging.

The biggest signal to Karen Holland that something was wrong came when Edward could no longer calculate a tip on a restaurant bill. Then, she recalled, his handwriting started to deteriorate and he began wandering off, unsure how to get home.