Updated

Older U.S. adults, particularly women, are more likely to use prescription sleep medications to try to get the minimum seven hours of sleep experts generally recommend, U.S. data released on Thursday showed.

Use of such pills, which include Sanofi SA's Ambien and other similar drugs, was significantly higher for those in their 50s as well as age 80 and older, according to the findings from the Centers for Disease Control and Prevention.

Overall about 8.6 million people, or 4 percent of U.S. adults reported recently using sleep medication, CDC's National Center for Health Statistics said in a report.

But data showed higher use among middle-aged adults ages 50 to 59 and the elderly.

Six percent of those ages 50 to 59 said they had taken a prescription sleep pill in the last 30 days, and 7 percent of those age 80 and older reported such use. In between, the numbers dip slightly below 6 percent for those in their 60s and 70s.

In comparison, just 2 percent of those aged 20-39 said they had recently taken a sleep aid.

CDC researcher Yinong Chong said people in their 50s could have trouble sleeping because of work and family stress.

"It gives the picture of a sandwiched group who has family, not only children but also probably elderly parents but still you're likely to be in the workforce, so you get squeezed at both ends in terms of family responsibility and job responsibility," she said.

Sleep may improve when people retire before potential chronic health problems kick in and begin interfering with sleep, Chong said, adding more study is needed.

The data also showed that 5 percent of women surveyed said they had recently taken a sleep aid compared to about 3 percent of male respondents, according to CDC's report. Chong said it was not clear why women were more likely to use the drugs.

While previous data have tracked prescriptions dispensed for sleep aids, the CDC said its study is the first based on a survey of actual use of such drugs.

Researchers for the Atlanta-based health agency's National Center for Health Statistics questioned a sampling of adults age 20 and older about whether they had used prescription sleep aids within the last 30 days and asked participants to show interviewers the prescription medication.

"You get how many people are actually using them," Chong said in an interview, noting that prescription data could include multiple prescriptions for one patient or prescriptions that are never filled or even used. "This is actual use."

Controversy over lingering effects

Prescription sleep aids have become somewhat controversial because their effect can linger even after some patients wake up.

The U.S. Food and Drug Administration has begun taking a closer look at sleep drugs, ordering lower-doses for Ambien and similar pills amid concerns that their active ingredient remained in patients' blood the following morning at levels high enough to make driving and other activities dangerous.

And just last month, the FDA rejected an experimental sleep drug from Merck & Co Inc, saying the proposed doses were not safe but that a lower-dose version might be acceptable.

Not surprisingly, respondents to CDC's study who said they slept five hours or less each night or those diagnosed with a sleep disorder were more likely to report using prescription aids.

Additionally, more whites and people with higher levels of education also reported greater use, the agency said.

Socioeconomic factors are likely behind those numbers, Chong said, since patients must be able to afford a doctor's care and the medication.

According to prescription data from IMS Health, Ambien and other versions of the drug zolpidem was ranked 15th among the most dispensed medications in the United States.