An analysis of government demographic data published this week reveals an astonishing spike in the number of Americans stricken with Alzheimer’s disease—an increase of 10 percent in just five years. The chief reason is one we could hardly regret: the great success of modern medicine.

The incidence of Alzheimer’s increases sharply with age, and many more Americans are living into their seventies, eighties, and nineties than ever have before. Among those fortunate enough to make it past age eighty-five, a whopping 50 percent are afflicted with Alzheimer’s or a similar form of dementia. The baby boomers are the first American generation to have lived their entire lives truly in the age of modern medicine (which we might roughly define as beginning with the introduction of penicillin into general use). That has made them the healthiest generation to date, and will surely make them the longest lived. It will also mean that for an enormous number of American families, the coming decades will be shaped by the contours of the slow mental (and eventually physical) decline brought on by dementia.

The advance of the disease can be emotionally excruciating for the patient’s loved ones, as the afflicted person is slowly lost to them but is still very much with them. The disease can also carry enormous economic costs for the families involved, since in middle and later stages patients often need constant and intense care.

We are thoroughly unprepared for the scale of the demographic shift to come, as our society (on average) grays in the coming years. Families will learn to cope, and the nation will find ways to afford the added burdens, but it will take time and it won’t be pleasant at first, as a whole set of complex emotional, ethical, and economic challenges rush at us.

Some have begun the work of thinking through these challenges. The President’s Council on Bioethics, for instance, released a report on the issue in 2005. Leon Kass (the Council’s former chairman) and Eric Cohen also wrote a powerful article on some related questions in the January 2006 issue of COMMENTARY. Many others are at work as well. But it’s fair to say that policymakers and the bulk of the public still have no idea what’s coming, and how the life of every American family will be affected.

Here’s a hint for anyone hoping to run for President ten years from now: learn everything you can about long-term care.