According to this report from the National Sleep Foundation, insomnia increases the risk for falls in the elderly:
Falling is a significant cause of health problems and injury among older adults. According to the Centers for Disease Control, in 2001, more than 1.6 million seniors were treated in emergency departments for fall-related injuries and nearly 388,000 were hospitalized. The problem is even worse among nursing home residents where as many as 75% of residents fall annually, twice the rate of seniors living in the community. Despite prevalent sleep problems experienced by many nursing home residents, use of sleeping pills has been contraindicated due to a concern that their use might contribute to falls. A recent study in Journal of the American Geriatrics Society shows that contrary to common beliefs, it may not be sleeping medication but rather insomnia that increases nursing home residents' risk of falling. The study included more than 34,000 Michigan nursing home residents over age 65. Participants who had untreated insomnia at the start of the study were 90% more likely to fall in the next six months compared with those who did not have insomnia. In contrast, those who were taking hypnotic drugs to treat their insomnia at the start were only 29% more likely to fall. Alon Avidan, MD, MPH, first author of the study, explained, "Our findings suggest that people whose insomnia is effectively treated are less likely to fall than untreated insomniacs."