Alzheimer's has struck more than five million Americans, up 10% from 5 years ago ('02).The number is expected to more than triple by 2050, absent a cure, as the 85-and-over population soars and boomers move into their late 60s and 70s. The disease afflicts 1 in 8 people 65 and over, and 42% of those past 85. Medicare spends three times as much caring for a dementia patient as for the average beneficiary ($13,207 a year vs. $2,454). (NY Times 3/21/07)