Alcohol brands that most underage drinkers consume are heavily advertised in the magazines that young people read, according to a recent study.

Researchers from John Hopkins University and Boston University said their findings add to evidence that alcohol ads can encourage kids to drink, and suggest that the alcohol industry's self-imposed standards on advertising are inadequate.

"We can't speak to what advertisers' intentions are," David Jernigan, co-author of the study and director of the Center on Alcohol Marketing and Youth (CAMY) at The Johns Hopkins Bloomberg School of Public Health, said in a statement. "But we can say there is clear evidence that 18- to 20-year-olds are the most heavily exposed to these ads."

For the study, researchers examined alcohol ads that ran in magazines in the United States in 2011 - with a particular eye toward the top 25 alcohol brands consumed by youth under the legal drinking age.

"All of the ads in our study were in complete compliance with the industry's self-regulatory guidelines," Ross said.

According to those standards, alcohol ads should be placed only in magazines where less than 30 percent of the readers are younger than 21. Yet, based on the new findings, underage readers see plenty of glossy magazine ads for beer and distilled spirits.

Based on their findings, the top 25 alcohol brands consumed by youth under the legal drinking age appeared much more effective in reaching young magazine readers, versus 308 other alcohol brands that are less popular with the underage crowd.

Manufacturers of 11 of the 25 brands most popular with underage males exposed 18- to 20-year-olds most heavily. The same was true for 16 of the top 25 brands among underage females. In all, those popular brands were five to nine times more likely to have 18- to 20-year-olds in their most heavily exposed audience, compared with all other brands.

"That's concerning," he added, "because that age group is at high risk of alcohol abuse and negative consequences from drinking."

Craig Ross, lead researcher of the study, said underage exposure to alcohol advertising would be reduced if the industry would agree to stricter standards -- such as limiting ads to magazines where less than 15 percent of readers are under age 21.

He added that parents could help by educating their kids, from a young age, to be savvy media consumers.

"Parents should take note that scientific evidence is growing that exposure to alcohol advertising promotes drinking initiation and is likely to increase the frequency of consumption for kids already drinking," Ross said.

The findings were recently published in the Journal of Studies on Alcohol and Drugs.