When Bob Cailleteau's daughter got married last year, he didn't even think of renting a tuxedo. Cailleteau may have been 91, but his heart was strong. His mind was sharp. And he had just been told by his doctor that he could reasonably expect to live to 105. He insisted on a dapper new suit; he knew he'd have occasion to wear it.

Then in December, he fell. He might have blacked out for a minute, but no one really knows why it happened, says Nancy Mills, 40, of Austin, the daughter who was just married. They just know that in the split second it took for him to hit the ground, his life changed — maybe forever.

That is how it often happens with adults 65 and older. One day they're fine. The next, they've fallen. Maybe they break a hip. Sometimes they hit their heads. Often, the consequences are dire.

Falls are much more common — and devastating— than many people realize, a point driven home by recent news of prominent older people falling. Sen. Robert Byrd, D-W.Va., former first lady Nancy Reagan and former UCLA basketball coach John Wooden all fell recently. All are said to be recovering.

Seniors falling "is a large, growing and, quite frankly, underreported health issue," says Elizabeth Wilson, spokeswoman for the National Safety Council, based in Chicago.

In fact, falls are the leading cause of injury deaths among people 65 and older, according to the Centers for Disease Control and Prevention. In 2005, 15,800 people 65 and older died from injuries related to falls, and about 1.8 million were treated in emergency rooms for such injuries, the CDC says. In 2000, falls cost $19.2 billion.

Often, falls lead to a downward health spiral because a senior has lost his or her mobility, Wilson says.

One in four people who have a hip fracture will die within a year from the fall, Wilson says. Another 50 percent will never return to the level of mobility before the fall.

And a CDC study released this month indicates that 5.8 million (15.9 percent) of adults 65 and older in the USA fell at least once during the preceding three months. Of those, 1.8 million sustained an injury that resulted in a doctor's visit or restricted activity for at least one day.

As the nation's 79 million baby boomers head into their senior years, health experts worry that falls will escalate.

"It is a very large public health problem," says Judy Stevens, an epidemiologist for the injury center at the CDC. "The more we look into it in detail, we get a broader picture on how widespread it is.