In the United States, the blood-alcohol limit may be 0.08 percent, but no amount of alcohol seems to be safe for driving, according to a University of California, San Diego sociologist.

A study led by David Phillips and published in the journal Addiction finds that blood-alcohol levels well below the U.S. legal limit are associated with incapacitating injury and death.

Phillips, with coauthor Kimberly M. Brewer, also of UC San Diego, examined official data from the Fatality Analysis Reporting System (FARS). This dataset includes information on all persons in the U.S. who were involved in fatal car accidents -- 1,495,667 people in the years 1994 to 2008. The researchers used FARS because it is nationally comprehensive, covering all U.S. counties, all days of the week and all times of day, and, perhaps most important, reports on blood-alcohol content in increments of 0.01.

All the accidents included in FARS are, by definition, severe. But the authors looked at different levels of accident severity by examining the ratio of severe injuries to minor ones

There are at least three mechanisms that help to explain this finding, Phillips said: "Compared with sober drivers, buzzed drivers are more likely to speed, more likely to be improperly seat-belted and more likely to drive the striking vehicle, all of which are associated with greater severity."

There also seems to be a strong "dose-response" relationship between all these factors, the authors write: The greater the blood-alcohol content, the greater the average speed of the driver and the greater the severity of the accident, for example.

The findings persist even when such potentially confounding variables as inattention and fatigue are excluded from the analysis.

"We hope that our study might influence not only U.S. legislators, but also foreign legislators, in providing empirical evidence for lowering the legal BAC even more," Phillips said. "Doing so is very likely to reduce incapacitating injuries and to save lives."
 

Olive oil can help prevent strokes in people over 65, a study suggests.

Researchers followed around 7,000 people aged 65 and over living in three French cities, for at least five years. They found those who used a lot of olive oil in cooking or as a dressing or dip had a lower risk of stroke than those who never used it.

The researchers say older people should be given new dietary advice regarding olive oil, based on the findings, which are published in the journal Neurology.

Lead author, Dr Cecilia Samieri, of the University of Bordeaux, said: "Our research suggests that a new set of dietary recommendations should be issued to prevent stroke in people 65 and older.

"Stroke is so common in older people, and olive oil would be an inexpensive and easy way to help prevent it."

The study found the stroke risk was 41% lower in those who regularly used olive oil compared with those who abstained, once other factors such as diet, exercise and weight were taken into account .

Commenting on the study, published in Neurology, Sharlin Ahmed of the Stroke Association, said: "Olive oil has long been known to have potential health benefits..

"It is believed that it could protect against conditions such as high cholesterol, high blood pressure and heart disease and so it's promising to see that it could have a similar protective function against stroke.
 

For grownups, drifting off for an afternoon snooze is often easier said than done. But many of us have probably experienced just how simple it can be to catch those zzz's in a gently rocking hammock.

By examining brain waves in sleeping adults, researchers reporting in the June 21 issue of Current Biology, a Cell Press publication, now have evidence to explain why that is.

The study finds that napping on a slowly swinging bed really does get us to sleep faster. To the researchers' surprise, rocking also changes the nature of our sleep, encouraging deeper sleep.

"It is a common belief that rocking induces sleep: we irresistibly fall asleep in a rocking chair and, since immemorial times, we cradle our babies to sleep," said Sophie Schwartz of the University of Geneva.

"Yet, how this works had remained a mystery. The goal of our study was twofold: to test whether rocking does indeed soothe sleep, and to understand how this might work at the brain level."

Schwartz, Michel Mühlethaler, and their colleagues Laurence Bayer and Irina Constantinescu asked twelve adult volunteers to nap on a custom-made bed or "experimental hammock" that could either remain stationary or rock gently.

All participants were good sleepers who didn't typically nap and did not suffer from excessive sleepiness during the day. Each participant took two 45-minute afternoon naps, one with the bed stationary and one with the bed in motion, while their brain activity was monitored by electroencephalogram (EEG).

"We observed a faster transition to sleep in each and every subject in the swinging condition, a result that supports the intuitive notion of facilitation of sleep associated with this procedure," Mühlethaler said.

Schwartz and Mühlethaler say the next step is to find out whether rocking can improve longer periods of sleep and to find out whether it may be useful for the treatment of sleep disorders, such as insomnia.