Lifestyle issues contribute to weight gain in teen girls

Teen girls who want to lose weight may need to consider how much they sleep, drink and surf the Internet, according to a study published online July 10 in the Journal of Pediatrics.

Researchers analyzed data from 4,427 girls ages 14 to 21 who were participating in the Growing Up Today Study, a cohort of children of subjects from the Nurses' Health Study II. An average weight gain of four pounds per year was associated with getting less than five hours of sleep a night, drinking more than two servings of alcohol per week and surfing the Internet for recreation for an hour or more at a time. Coffee did not appear to play a role. However, the authors noted that the caloric content of many coffee drinks has increased since this population was surveyed in 2000 and 2001. The other worry is the cumulative effect of these additional pounds as these lifestyle issues become hard-to-break habits.

"These particular factors are potentially very important with regard to excess weight gain because as girls get older, they spend more time on the Internet while getting less sleep, drinking more coffee and, possibly, also beginning to consume alcohol," said Catherine Berkey, ScD, lead author and a lecturer in medicine at Harvard Medical School in Boston.

Experts praised the paper for attempting to quantify the many lifestyle factors that may contribute to weight gain among adolescent girls.

"This study makes perfect sense," said Ellen Rome, MD, MPH, head of adolescent medicine at the Cleveland Clinic.

Most suspect these behaviors are connected to weight because they play a role in sedentary behavior and excess calorie consumption. For example, teens who spend a lot of time in front of computers would have, before the Internet, been sitting in front of a TV. Therefore, adolescent medicine specialists are calling for physicians to ask about total screen time rather than just television hours.

"The Internet is the new watching television for this particular generation of adolescents and young adults," said James Farrow, MD, professor of pediatrics and medicine and director of the student health service at Tulane University in New Orleans. "It's a sedentary way of socializing instead of playing a sport or something like that, and I would not be surprised if they were eating at the same time they were on the Internet."

Alcohol provides significant liquid calories and can lead to sleep disturbances. This lack of sleep quality, in turn, can lead to metabolic issues that can add pounds. The resulting daytime sleepiness may mean that teens will not have the energy to participate in physical activity.

"It becomes a vicious cycle. Alcohol can significantly disrupt [one's] sleep cycle, and if they're more sleepy during the day, they're not going to be as active," said Tonya Chaffee, MD, MPH, associate clinical professor of pediatrics at the University of California, San Francisco.

Those who work with adolescents also would like to see more analysis of how these factors may affect the weight of teen boys, and of the impact of all caffeinated drinks, not just coffee.