Drunken sports fans shy away from having their blood alcohol measured, but a small U.S. study hints that a "significant number" of people attending professional sports games may have high alcohol levels that could increase their chances of being involved in traffic accidents or crime.

For the study, published in Wednesday's online issue of the Journal Alcoholism: Clinical & Experimental Research, investigators conducted blood alcohol content (BAC) tests on 362 adults at 13 professional baseball games and three football games between May and October 2006.

They found that 8.4 per cent of the subjects had a BAC higher than the legal limit of .08

"Our sample size was small, partly because of the difficulty of getting fans to submit to a BAC test after a game," said Darin Erickson of the University of Minnesota, the study's lead author.

"But if we assume that it represents individuals attending professional events, it means that, on average, about 5,000 attendees leaving one National Football League event would be above the legal BAC limit for driving. That's a lot of drunken individuals who could be involved in traffic crashes, assaults, vandalism, crime and other injuries," he added in a news release.

Similarly, a Canadian study published in 1992 found that a higher proportion of alcohol-related traffic accidents occurred after soccer, baseball and football games in Toronto compared with pre-game periods and compared with the same period on non-game days.

Erickson and his co-authors found that:

• Fans under 35 years of age have nearly eight times greater odds of having BAC levels above the limit of .08.
• Those who drank at tailgating parties have 14 times greater odds of being legally drunk, compared with fans who had not tailgated.
• Fans attending Monday night football games were more likely to have positive BACs compared with those attending games on other days.

Researchers divided the BAC results into three catgories: 0; .001 to .079; and .08 or higher.

Those who were in the highest BAC category reported consuming, on average, 6.6 drinks compared with 3.7 drinks for the mid-range category and 2.8 drinks for those who registered zero blood alcohol.

"Our findings show a significant number of attendees at professional sporting events have elevated BAC levels, particularly young adults and those who participated in tailgating activities," the study's authors concluded. "Given the high propensity for alcohol-related problems at these events, additional efforts to reduce levels of alcohol consumption prior and during these events are recommended."

The researchers acknowledged their data collection method has some flaws, such as an inability to accurately track refusals to participate given the narrow window of opportunity to recruit participants when a game ends.

The study was funded by the Substance Abuse Policy Research Program of the Robert Wood Johnson Foundation.