A recent study out of Taiwan reveals a startling statistic: From a pool of 16,000 respondents, 15 percent of 13 to 15-year-olds said they had tried vomiting to lose weight in the last year, and nearly 16 percent of 10 to 12-year-olds said they had.
The behavior, researchers wrote in the Journal of Clinical Nursing, was more pronounced in children who engaged in what are generally regarded to be unhealthy behaviors. For example, more than 20 percent of those who said they'd tried vomiting at some point also admitted to eating fried food on a daily basis. And another 18 percent said they sat at a computer for more than two hours a day.
"It showed that self-induced vomiting was most prevalent in adolescents who had a sedentary lifestyle, slept less and ate unhealthily," Dr. Yiing Mei Liou, the study's lead author, said in a statement.
The study has attracted some media attention, and many reports have raised the question of whether bulimia is on the rise in younger and younger kids.
"First, you have to distinguish between purging and bulimia nervosa," said Dr. Terry Schwartz, clinical director for the University of California San Diego's School of Medicine. "It's like asking whether a kid has tried marijuana versus if they have a marijuana problem. It's a very different diagnostic issue."
The diagnostic criteria for bulimia nervosa ask whether or not a person has engaged in episodes of binge eating followed by self-induced vomiting at least twice a week for three months or more. Using that definition, the National Institute of Mental Health estimates that the lifetime prevalence of bulimia nervosa is 0.6 percent in the adult population of the U.S.
But those who are not necessarily bulimic do experiment with self-induced vomiting.
According to a 2009 study by the Centers for Disease Control, 4 percent of teens in the U.S admitted to having vomited or taken laxatives to lose weight within the 30 days prior to the survey.
"Most people who suffer from an eating disorder do not meet specific criteria for anorexia nervosa and bulimia nervosa," said Dr. Pamela Keel, a member of the clinical psychology faculty at Florida State University. "Our tendency to study the disorders we have defined creates a gap between the problems that people have and what we know about those problems."
Keel's own research has focused on people who repeatedly purge after eating a normal or small amount of food -- a condition known as purging disorder. She explains that those people often have subjective and physiological responses to food intake that are distinct from those of a person who suffers from bulimia nervosa.
That, says Dr. Evelyn Attia, director of the Columbia University Center for Eating Disorders, raises some interesting questions about whether there are far more people experiencing these responses than what a clinical program sees. Attia added that Keel's research, as well as the new study from Taiwan, are both raise important questions.
"Are there these behaviors among younger kids, and do they indicate they are at risk for what qualifies as a formal eating disorder diagnosis?" Attia asked. "We don't know. But it suggests we should be looking at these things."
One roadblock to doing so -- at least in the clinical setting -- is that health care providers simply may not think to ask about purging issues in children so young.
"It's unusual to ask about dieting behavior in a 6-year-old, or to ask about self-induced vomiting in someone who hasn't hit puberty yet," Attia explained.
But this latest study suggests that perhaps a provider or parent should, particularly if they notice warning signs that Schwartz said can include weight loss, frequently disappearing to the bathroom, not eating with the family or eating large amounts of food and not gaining weight.
"Those are the things to watch for in your children," she said. "Because I would say that it does appear to be the case that this is affecting younger males and younger females than we have seen before."