Teens with Anorexia May Be 'Dangerously Ill' Even if They Are Not Underweight

young girl speaking with doctor in a clinic
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Teens and young adults with anorexia are at risk of life-threatening illness even if their weight falls within a "normal" range. 

That's the conclusion of a new study that looked at "atypical anorexia," or cases in which patients show all the symptoms of anorexia with the exception of low body weight. In the past, these cases were considered less severe than typical anorexia cases, but the new study found that both types show the same signs of severe malnutrition. "Patients with atypical anorexia are just as sick, medically … but they may be even sicker, psychologically," said Dr. Neville Golden, a professor of pediatrics at the Stanford School of Medicine and co-author of the new study. Although recognized in the diagnostic manual for mental health disorders, the DSM-5, atypical anorexia may remain underdiagnosed, Golden said.   

"The assumption is that doctors in the community are not recognizing it," he said. The oversight may place patients at risk of cardiac arrest, bone degradation and even death, Golden and his colleagues found. 

The new study, published Nov. 5 in the journal Pediatrics, shows that there's no connection between an anorexic patient's weight and the actual severity of their condition. In the end, the number on the scale matters far less than the sheer amount of weight patients lose over the course of their illness — both normal-weight and underweight patients fare worse the more weight they drop.

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"There's no weight or BMI that equals [an] eating disorder," said Dr. Casey Cottrill, the medical director of the eating disorders program at Nationwide Children's Hospital in Columbus, Ohio, who was not involved with the study. Over the last five to 10 years, the number of normal-weight people hospitalized for anorexia treatment has spiked, she said. Recent studies estimate that one-third of patients admitted to hospitals for anorexia treatment are of normal weight. In both atypical and typical cases, the signs of malnutrition appear the same, but patients of normal or above-average weight may suffer longer before being noticed. 

In light of this, doctors must watch for signs of disordered eating and malnutrition in all patients, regardless of size, Cottrill said.  

Dramatic weight loss 

Although atypical anorexia has gained recognition, still, "when one thinks of malnutrition, one thinks of low weight," Golden said. To learn whether low-weight anorexic patients actually fare worse in clinic, Golden and his colleagues organized the largest, most comprehensive assessment of normal-weight adolescents with anorexia to date. 

The study compared 50 teens and young adults with atypical anorexia with 66 patients who met the traditional diagnostic criteria, meaning their weight fell below 85% of what would be expected for their height and age. The participants ranged in age from 12 to 24 years old and received treatment for their disorders during the study. More than 90% of participants were female. (Anorexia is about 3 times more common in females compared with males, according to the National Eating Disorders Association (NEDA).)  

The authors compared the patients' current weights, histories of weight loss and vital signs; and found that regardless of participants' weight at admission, those with more dramatic weight losses appeared more severely ill.

Patients who lost a large amount of weight, fast, displayed the lowest heart rates among those in the study. In fact, for every 2% increase in the rate of weight loss per month, patients' heart rates measured 1 beat per minute slower in the hospital. A dangerously low heart rate points to a larger problem: poor nutrition leaves the heart with too little fuel to pump properly while also forcing the body to break down heart tissue  for much-needed energy, according to NEDA. Clinicians usually hospitalize patients whose heart rates clock below 50 beats per minute, as their condition can quickly deteriorate into complete heart failure, Cottrill said.   

Related: What Is Mental Health?

Patients with atypical and typical anorexia showed similar dips in other critical measures of health. Both groups had dangerously low blood pressure and became dizzy when moving from lying down to sitting up or standing. Both groups showed deficiencies in key electrolytes such as potassium, phosphorus and magnesium — nutrients that help vital organs like the heart running smoothly. The patients who lost the most weight, or had been losing weight for an extended period, had the lowest electrolyte levels.    

All female patients who had begun menstruating stopped having regular periods, meaning their bodies were no longer producing enough estrogen to maintain their normal cycles. Without estrogen, the growing patients' bones could not absorb calcium as they should during puberty, Cottrill said. 

Overall, both groups of patients appeared similar on all counts — except one. Those with atypical anorexia actually ranked worse on a questionnaire designed to measure the severity of their eating disorder psychopathology. The poor scores suggest that those with atypical anorexia may be more fixated on losing weight, restricting their food intake and burning off calories than those with typical anorexia. Anecdotally, the patients seemed "very fearful of getting back to their [original] weight," Golden said.

Future studies 

Future research should investigate the best treatment for cases of atypical anorexia, particularly cases in which patients are overweight or obese, since very little data exists in this area, Cottrill said. Weight gain normally comes along with both the physical and psychological treatment of anorexia, but with overweight patients, it's difficult to gauge how much weight they need to regain. More research must be done on how different bodies react to malnutrition and how best to treat patients of different sizes, Cottrill said. 

In addition, when treating obesity, doctors must learn how to help people lose weight sustainably, without resorting to drastic measures, Golden said. By monitoring patients more closely, perhaps physicians can catch poor habits before they fester into a full-fledged eating disorder, he suggested. The first step, of course, is to raise awareness of what disordered eating looks like.       

"I think there's a lack of awareness of atypical anorexia nervosa, even among clinicians," said Dr. Avinash Boddapati, a child and adolescent psychiatrist in the Northwell Health network, who was not involved with the study. As a psychiatrist, Boddapati said he can address the underlying emotional distress and harmful coping mechanisms that lead to disordered eating. But to tackle the problem head-on, pediatricians and parental guardians need to work together to monitor signs of atypical anorexia. 

"The big take home message is to focus, not just on the weight, but on the rate of weight loss," he said.  

Psychiatrists can also screen for rapid and extensive weight loss in their patients, "even kids [who fall] within a normal weight range," said Dr. Peng Pang, an adolescent psychiatrist at Staten Island University Hospital in New York. First, mental health professionals should ensure that their patients are physically stable, and refer them to a hospital if their health may be compromised,  said Pang, who wasn't involved with the study. Then, once the patient's vital signs are restored, psychiatrists can work with patients to find new, sustainable coping mechanisms.      

"Regardless of the body weight, I think the message is that you have to intervene, immediately and aggressively," Pang said.

Originally published on Live Science. 

Nicoletta Lanese
Channel Editor, Health

Nicoletta Lanese is the health channel editor at Live Science and was previously a news editor and staff writer at the site. She holds a graduate certificate in science communication from UC Santa Cruz and degrees in neuroscience and dance from the University of Florida. Her work has appeared in The Scientist, Science News, the Mercury News, Mongabay and Stanford Medicine Magazine, among other outlets. Based in NYC, she also remains heavily involved in dance and performs in local choreographers' work.