WOMEN OVER the age of 70 who sleep five hours or less per night may be at greater risk of having a fall than those who sleep more than seven or eight hours a night, according to a new study.
The report was published in the American journal Archives of Internal Medicineyesterday.
In Ireland, falls are the most common cause of admission to nursing home care and frequent falls are associated with faster physical and cognitive decline, according to medical experts on ageing here.
"About one-third of adults older than 65 experience falls each year. Insomnia and disturbed sleep as well as the use of benzodiazepines [hypnotic medications to treat insomnia] are increasingly common in older adults," the article said.
"It is not established whether it is poor sleep or medications used to treat sleep disturbances that explain the increased risk of falls in those who are prescribed such medication," it added.
Katie L Stone PhD, of the California Pacific Medical Center Research Institute, San Francisco, and colleagues used monitoring devices and sleep diaries to measure sleep, sleep efficiency (the percentage of time in bed spent sleeping) and frequency of falls in 2,978 women aged 70 and older.
On average, participants slept for 6.8 hours a night and spent an average of 77.2 minutes awake after initial sleep onset. The average number of falls one year after the collection of sleep data was 0.84.
"A total of 549 women [18.4 per cent] had two or more falls during the year after the sleep assessments," the authors said.
The risk of having two or more falls during the following year was higher for women who slept five hours or less per night compared with women who slept more than seven to eight hours.
Women with greater wake time after sleep onset (120 minutes or more) were 1.33 times more likely to fall than those who spent less than 120 minutes awake.
In total, 214 women in the study (7.2 per cent) reported current use of benzodiazepines. The authors said such medication was associated with a 1.34 -fold increase in the risk of falls.
Prof Rose Anne Kenny of Trinity College and head of the falls and blackout unit at St James's Hospital said: "We have known for a long time that sleeping tablets contribute to falls but we don't know how.
"All psychotropics, such as those given for depression, psychiatric illness or sleeping are a major risk factor.
"As we get older, we sleep less and that's probably because ageing alters our sleep pattern but possibly because we are on more medications. Half of people over 65 in Ireland are on three or more medications."
Prof Kenny is currently working on guidelines on falls for the American and British Geriatric Societies, which will be published in December.
She said one of the recommendations was that medical professionals should try, where possible, to avoid prescribing psychotropic drugs.
Prof Kenny is also involved in the Tril project, a major three-year study on fall prevention, funded by the IDA and Intel.
Prof Des O'Neill, professor of medical gerontology at Trinity College and Tallaght hospital, said further study was needed into whether falls were as a result of impaired sleep, or whether there were also "subtle or not-so-subtle" forms of disease at work. He said the use of benzodiazepines in general also needed to be examined and that they should only be prescribed for a maximum of four to six weeks.
"There is some suggestion that the use of them has entered into our culture and they need to be cut down."