Eating Habits and Insulin Misuse Among Young Adults with Diabetes

A recent long-term follow-up study of teenagers with type 1 diabetes mellitus offers the first comprehensive view of the outcome of childhood and adolescent diabetes and the effects of the disease upon disordered eating (Diabetes Care 2007; 22:1956).

A study from youth to young adulthood

The authors took a representative sample of 76 teens (43 males, 33 females) with type 1 diabetes, and followed them over eight years, to examine any insulin misuse and weight changes and their relationship to glycemic control and diabetic complications. Sixty-five (86% of the original group) were re-interviewed eight years later, when they were young adults. The group’s eating behaviors were assessed with a standardized Eating Disorder Examination, and height and weight were measured and body mass index (BMI) was calculated. Three consecutive urine specimens were measured for albumin\creatinine ratio and other significant complications related to diabetes were recorded. Glycolated hemoglobin levels were used to assess glycemic control.

Increasing concerns about weight and shape

Weight and BMI steadily increased from adolescence to young adulthood. Females were overweight as teens, and both sexes were overweight as young adults. Concerns about weight gain and body shape increased significantly for both sexes from adolescence to young adulthood. This concern was reflected in increased dietary restraint. While all the young women showed signs of disordered eating as teens and young adults, none met the criteria for anorexia nervosa or bulimia nervosa at either evaluation.

Misusing insulin

Ten females (30%) and no males admitted misusing insulin to control their weight. Five women with microvascular complications had intentionally misused insulin to avoid gaining weight. The women were also significantly more concerned about their weight and shape at follow-up than they had been as teens. This concern was seen in dietary restraint; 72% of those who expressed concerns about weight at follow-up had a higher BMI than at baseline. Males had a similar pattern of increased concern, although at much lower levels than did females at both assessments.

Of the 10 women who misused insulin, five admitted they had been misusing insulin in their teens, even before the baseline interview (see box). The degree of misuse varied widely: one woman admitted giving herself a maximum of two injections a week for seven years. Four females who had misused their insulin were among the six subjects classified as having a clinical eating disorder not otherwise specified (EDNOS). No women admitted to misusing insulin at the time of the second follow-up interview.

The toll of insulin misuse could be seen in the microvascular complications that affected 46% of the women who admitted misusing insulin. Two females had laser-treated proliferative retinopathy, two had nephropathy, and one had both laser-treated proliferative retinopathy and nephropathy. There were no significant relationships between either disordered eating at baseline or insulin misuse and the development of diabetic complications.

Males were only marginally overweight at baseline but significantly overweight at follow-up, while the females were significantly overweight at both interviews. The authors hypothesize that the increase in weight during adolescence and early adulthood might be associated with relative leptin resistance—females were more resistant and gained greater fat mass than males, consistent with the higher BMIs reported among females in this study.

The association between the degree of glycemic control and features of eating disorders was unclear, according to the authors. Disordered eating behavior alone in adolescence was not related to increased risk of complications, but deliberate insulin misuse appears to be more important, although not statistically significant in this small sample. The authors concluded that while their study did not show evidence of an increase in the prevalence of bulimia nervosa, it did illustrate the continuing and increasing concerns about weight and shape among people with type 1 diabetes, especially among females.