Extreme Obesity Linked to Dangerous Behaviors in Teens

Study: Smoking, Risky Sex More Common in the Heaviest High School Students

By Brenda Goodman
WebMD Health News

Reviewed by Laura J. Martin, MD

April 25, 2011 -- Teens with extreme obesity may engage in risky behaviors at similar rates as those with a healthy weight, but sometimes in more dangerous ways, according to a new study.

The government-funded research looked at the risks for sex, alcohol, illegal drugs, or suicide attempts reported by more 9,000 high school students who took part in a nationwide survey.

The study looked at the heaviest high school kids -- the ones who top the growth charts for their height and weight and have a body mass index (BMI) greater than or equal to the 99th percentile. That starts around 220 pounds for a 15-year-old of average height.

"This group of teens is understudied, and we know that they're at major health risks for their obesity, but we really didn't understand how typical they were in terms of their teen-like behaviors," says study researcher Meg H. Zeller, PhD, staff psychologist at Cincinnati Children's Hospital Medical Center in Ohio.

Heaviest Teens Taking Risks

In general, Zeller and her team found that being big doesn't necessarily make teens any less likely to experiment with things like cigarettes, sex, or drugs than their normal-weight peers.

Because obesity is known to be socially isolating and many of those things are tried in social settings, she says that finding was a surprise.

And some kinds of risks, like smoking, turned out to be even more common in very obese students.

Extremely obese girls were about twice as likely as slimmer students as to have ever tried cigarettes or to be current smokers.

Extremely obese boys were about 50% more likely than their normal-weight counterparts to have ever tried cigarettes or to have started smoking before age 13.

Although heavy girls were about half as likely as their slimmer peers to have ever had sex, when they did have intercourse, they were nearly five times more likely to do so under the influence of alcohol or drugs.

"That's a more dangerous scenario for someone to be having sex," Zeller says.

Previous studies have shown that sex is less likely to be protected, and more likely to go further than originally planned, when alcohol or drugs is involved.

"Navigating relationships is hard for any adolescent girl, let alone an adolescent girl who's carrying this burden of weight," Zeller says. "These kids are in situations where they're really vulnerable, and we need to be paying closer attention to that."

Independent experts praised the research but said certain cautions apply to the interpretation of the study's findings.

"There hasn't been a lot of study on this issue," says Tilda Farhat, MD, MPH, a postdoctoral fellow at the National Institute of Child Health and Development in Bethesda, Md.

Farhat points out that because of the study's design, the researchers can't prove that obesity is causing the uptick in certain risk behaviors, and more research is needed to understand why it's happening.

But certain pieces of the puzzle are starting to come together.

"There is research showing that overweight and obese teens are more likely to be facing social isolation, for example, which may lead to stress. And substance use is a known mechanism for coping with stress," Farhat says. "So we do know some of these factors, but we don't know a lot about how social isolation or stress is leading to risky behavior. So this is important to document."


What causes tooth decay? See Answer

Health Solutions From Our Sponsors

SOURCES: Ratcliff, M. Pediatrics, May 2011.Farhat, T. American Journal of Preventive Medicine, March 2010.Meg H. Zeller, PhD, staff psychologist, Cincinnati Children's Hospital Medical Center, Ohio.Tilda Farhat, MD, MPH, postdoctoral fellow, National Institute of Child Health and Development, Bethesda, Md.

©2011 WebMD, LLC. All Rights Reserved.