July 5, 1997

Adolescence is a painful time. As the body undergoes a bewildering array of physical changes, so do the emotions -- leaving the inner self to wonder who am I becoming and what I can I do to control this metamorphosis? Coincident hormonal surges that prompt sexual curiosity can fuel a host of related doubts about one’s attractiveness.

Many teenagers respond by adopting extraordinary tactics to remain fashionably slim. A new study now finds that adolescent girls with insulin-dependent diabetes -- one of the most common chronic disorders affecting North American youth -- often select what are for them particularly dangerous strategies.

Gary M. Rodin, head of psychiatry at Toronto Hospital in Ontario, said his curiosity was initially piqued by the unusually high number of young diabetic girls that were being referred to him because of eating disorders.

Though only about 5 percent of nondiabetic young women exhibit serious eating problems, ones that qualify as "psychiatric disorders," Rodin says, another 20 to 25 percent exhibit milder, though still quite abnormal eating patterns. For instance, these women may periodically induce vomiting or use laxatives to expel some of what’s been eaten before it’s been fully digested.

Among diabetic teens, roughly one-third acknowledged some type of aberrant weight-control strategy. They often engaged in binge eating or withholding insulin. "We wanted to know," Rodin says, "if you see somebody at 14 or 15 with these problems, is it temporary? And what are the health consequences?"

In the June 26 New England Journal of Medicine, his team now reports finding that this population indeed has a very high rate of eating disorders, that their maladaptive behavior persists to at least adulthood, and that it sets in motion a series of degenerative changes that place these young women at strikingly high risk of developing blinding eye complications.

"What we found is fairly disturbing to us," Rodin told Science News Online. "One-third of the girls were trading off an increased risk of medical complications in order to prevent weight gain."

When diabetics begin taking insulin, especially intensively, they tend to gain weight. It’s not unusual for them to put on as much as 10 pounds. At the same time, individuals beginning insulin therapy also revamp their diet and eating patterns. Not only must they sharply restrict their intake of sugars and other carbohydrates, but they must also coordinate the timing and size of their meals to when and how much insulin they take.

"What we think happens," Rodin says, "is that the combination of [insulin-induced] weight gain and dietary restriction in a susceptible young woman may set in motion a cycle of dieting and binge eating." While nondiabetic individuals may tolerate the occasional bingeing with no ill effects, eating large amounts of food unpredictably can prove dangerous for diabetics. It raises their blood sugar concentrations, which somehow triggers damage to the body’s small blood vessels.

Rodin's study found, however, that many young diabetic women engage in a weight-control practice even more dangerous than bingeing. They deliberately forego a dose of insulin or sharply curtail how much they take. "We were somewhat surprised by how many girls did this," Rodin says. "Not just the ones with eating disorders, but one-third of the whole group said that, to prevent weight gain, they sometimes took less insulin than they required."

Sugars and starches from the food consumed break down into glucose, a sugar that fuels the body’s operations and the production of new tissues. The body cannot use that sugar, however, without insulin, a hormone produced by the pancreas. Diabetic teens learn this -- and reason correctly that by withholding insulin from their system, they can prevent the body from fully using what they’ve eaten. The result: They lose weight.

But this strategy can exact a perilous toll. When Rodin’s study began, 7 of the 91 young women had been sabotaging their prescribed diet or insulin-administration schedule at least twice weekly for 3 months. Four years later, six of the seven -- 86 percent -- had developed early signs of diabetic retinopathy. The condition is caused by the deterioration of tiny blood vessels that supply oxygen to the eye’s retina, the tissue that transmits visual signals to the brain.

Only 43 percent of the 14 women who had occasionally engaged in such maladaptive dietary behaviors exhibited evidence of retinopathy. Among women who reported no such tactics, a mere 24 percent had developed incipient retinopathy.

The scientists looked for other types of diabetic complications that might be linked to lack of blood-sugar control but found nothing definitive. Says Rodin, "It might just take longer to occur."

Some types of eating disorders can be detected. Frequent induced vomiting erodes the enamel on the teeth. Anorexic patients often look emaciated. But within the group of diabetic teens that Rodin studied, even girls who were bingeing or withholding insulin tended, on average, to be normal weight and appear healthy. As a result, he says, "we think this often goes undetected."

Part of the message that these researchers therefore want to get out to the medical community and the families of diabetic patients is that when a girl’s blood sugar does not remain under control -- for reasons that can’t be readily explained -- "consider the possibility that there is an eating disorder or that the girl might not be taking all of her prescribed insulin."

The next question is what to do about it, because all of the girls who engaged in risky behaviors knew what they were doing. Hoping that intensive counseling might help, Rodin’s team has set up a series of six group meetings for the girls and for the families of the girls to discuss issues of dieting, weight, self esteem, body image, and the role of insulin in controlling the development of diabetic complications.

"We’re still in the middle of the trial," Rodin says, "but the preliminary results are very encouraging. After 6 months, we’re seeing a reduction in these [maladaptive dieting] behaviors."

Rydell, A.C., G.M. Rodin, et al. 1997. Disordered eating behavior and microvascular complications in young women with insulin-dependent diabetes mellitus. New England Journal of Medicine 336(June 26):1849.

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Fackelmann, K.A. 1994. Genome sweep finds two new diabetes genes. Science News 146(Sept. 10):164.

_____. 1993. Regimen slows diabetic complications. Science News 143(June 19):388.

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_____. 1995. Food for healing. Science News 148(Sept. 2):158.

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American Diabetes Association
1660 Duke Street
Alexandria, VA 22314
WEB: http://www.diabetes.org

Juvenile Diabetes Foundation
The Diabetes Research Foundation
120 Wall Street
New York, NY 10005-4001
Phone: 1-800-JDF-CURE (or 212-785-9500)
FAX: 212-785-9595
E-mail: info@jdfcure.com
WEB: http://www.jdfcure.com

Gary M. Rodin
Department of Psychiatry
Eaton Wing 8-222
Toronto Hospital
200 Elizabeth Street
Toronto, Ontario M5G 2C4
Canada

This week's Food for Thought is prepared by Janet Raloff, senior editor of Science News.

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