Falls are the leading injury cause of death among senior citizens, according to the Centers for Disease Control and Prevention. About one third of adults aged 65 and older fall each year, with 20 to 30 percent suffering moderate to severe injuries, the CDC says. Older adults are hospitalized for fall-related injuries five times more often than they are for injuries from all other causes combined.

Though the rate of fall-related fractures is twice as high among women as it is among men, men are 49 percent more likely to die from a fall than women are, the CDC said.

"Usually a fall is a combination of numerous factors," said Dr. Fred Harchelroad, director of emergency medicine at Allegheny General Hospital.

The muscles of senior citizens are weaker, Dr. Harchelroad said, and many suffer from medical conditions that affect their balance.

"People who have diabetic neuropathy don't have 100 percent sensation in their feet or fingers, so they can't really tell where their foot is going," he said.

About 60 to 70 percent of people who have diabetes have some form of neuropathy, according to the National Diabetes Information Clearinghouse. The highest rates of neuropathies are among people who have had diabetes for at least 25 years.

Both Allegheny General Hospital and the University of Pittsburgh Medical Center are among the nation's leaders in research in how to help seniors avoid falls, and to mitigate the damage that results from them.

Dr. Jessie VanSwearingen, who works in the mobility clinic of UPMC's geriatic center, is researching progressive walking disability, which she describes as a slow, gradual decline in multiple systems that occurs as people age.

"The vast majority of falls are from people who walk some and get out of the house about once a week," she said. "The more times you fall, the more likely you are to fall again."

Dr. VanSwearingen and Dr. Harchelroad agree the best way to prevent falls is to make sure the home environment is safe.

"Environmental changes are important," Dr. VanSwearingen said. "Have good light in all the rooms and stairways. No throw rugs."

"Make sure cords are hidden," Dr. Harchelroad said. "Make sure you don't have a cord in the area where you are walking. And watch out for slippery floors."

Have your eyes checked regularly, the doctors say.

"It's amazing how much vision influences walking," Dr. VanSwearingen said. "In the clinic, we pay a lot of attention to how well people see."

Regular exercise reduces the risk of falls, the doctors say.

"Any exercise that promotes balance is going to be a plus," Dr. Harchelroad said. But since most people fall while walking, the best form of exercise to reduce the likelihood of falling is walking, he said.

"If you practice anything, you get better at it," Dr. Harchelroad said. "If you walk every day, you get better at it."

Exercises that strengthen the core are also important, because they help people to keep proper balance while they're walking, Dr. VanSwearingen said.

"Your feet do the walking," she said. "Your hips keep your center of mass over your feet."

Betty Perkins-Carpenter, a former Olympic swimming coach, offers six simple steps in her best-selling book, "How to Prevent Falls":

1. Stretch in bed. By stretching, you have alerted your sensorimotor system and gross motor system.

2. Do balance exercises. Start by doing them with your hands on a sink or a dresser. After you have become more confident in the solidity of our your balance, briefly remove your hands from the furniture.

3. Bounce a tennis ball on the floor. As you bounce the ball, you are looking down at the patterns on the floor, which helps you become more alert to the edge of a rug, or a curb outdoors.

4. Walk when you are talking on the phone. It's more challenging to stay balanced because you are thinking about something else.

5. Dance with a pillow to music. Older people are reluctant to walk backward for fear of falling, but people who are dancing move forward and backward without thinking.

6. Practice making your body go limp, so if you do fall, you'll fall correctly. A stiff body breaks. A limp body bends.