Study: 1 in 5 drinkers is underage, drinks more and stays later at bar

August 19, 2009

GAINESVILLE, Fla. — As many as one in five alcohol-consuming customers in bars is underage, and underage patrons tend to stay later at night, according to a new University of Florida study.

The study is significant because it underscores the dangers of underage drinking, both to participants and to the wider public.

“That there are a fair number of underage people in the bars who are intoxicated may have implications for their future involvement with alcohol,” said Dennis Thombs, a professor in UF’s department of behavioral science and community health who led the research. “It is helping to set a pattern of chronic bar drinking for the college years and possibly beyond.”

Additionally, a study published in Journal of Studies on Alcohol found underage drinking costs Florida residents $3.7 billion in 2005, including work loss, medical care, and pain and suffering.

The new study, published in the June issue of the Journal of American College Health, is unusual in that it obtained breath samples and interview data from bar-goers as they were leaving rather than relying on self-report surveys that ask sober students to recall their alcohol use in the past two weeks or 30 days, said Thombs, who led the research.

The later it was at night, the younger the customers were who left the bar, so that by the time the drinking establishments closed at 2 a.m. the median age of the exiting patrons was 19 years old, he said. In addition, for each successive hour the bars were open a greater share of patrons intended to drive and their breath-alcohol levels increased as the evening wore on, Thombs said.

So many bar-drinking customers are underage because they can get away with it, Thombs said. “It’s no big secret that the management of drinking establishments in campus communities is not very thorough in checking I.D.’s,” he said.

The attraction of taking a risk that is illegal and making the most of it may explain why such a large proportion of underage customers stay late at bars and drink more, Thombs said.

“From a developmental perspective, college students are away from home and parental supervision for the first time, there are likely to be some who take advantage of their new options to party and have fun,” he said. “As students get older, it’s less exciting for them. They’ve done that before.”

The researchers collected information on 305 men and 164 women — 92 percent of whom were college students — outside bars in the midtown bar district in Gainesville on four nights in July and August 2007 between 10 p.m. and 2:30 a.m. Participants were interviewed as they left the bars and walked out onto the sidewalks. Then they blew into a hand-held breath-testing device to determine their blood-alcohol levels. In addition, they filled out a 15-item survey about their drug use that night and during the past 30 days. One in five who reported drinking that night in a bar acknowledged being under the legal drinking age of 21, Thombs said.

More than half of the participants were highly intoxicated upon leaving the bar, Thombs said. Fifty-five percent of the men and 59 percent of the women had blood-alcohol levels of 0.08 — the alcohol level at which a person is considered to be legally impaired — or higher, he said.

Between 10 and 11 p.m. 7.4 percent of those interviewed between those times intended to drive off within the hour, compared with 18.8 percent between 11 p.m. and 12 a.m., and 27.2 percent between 12 and 1 a.m., and 38.6 percent between 1 and 2 a.m. After the bars closed, the percentage dropped to 7.9 percent.

From 10 p.m. until 2 a.m., customers’ median breath levels rose from 0.05 to 0.09, he said.

“As the night goes on it becomes clear that bar patrons intending to drive become more and more intoxicated, underscoring concerns that a great deal of high-risk driving takes place late at night in campus communities,” he said.

A number of measures could be taken to reduce the incidence of intoxicated bar patrons who drive, including setting earlier last-call times for serving alcohol, eliminating drink specials late at night and increasing safe ride services, he said.

While one quarter of customers who drank alcohol reported intending to drive after leaving the establishment, the proportion rose to nearly one half of those who used both alcohol and marijuana, said Thombs, who works in UF’s College of Public Health and Health Professions.