Summary

An 11 year follow-up study shows that women with type 1 diabetes who restrict their insulin intake are three times more likely to die and also have a higher risk of complications compared to women who take their insulin as instructed.

Introduction

Type 1 diabetes is an autoimmune disease in which the pancreatic cells do not produce the hormone insulin. It used to be a death sentence before the introduction of insulin medication in the 1920s. Regular administration of insulin keeps blood glucose (glycemic) levels steady and protects the diabetic from complications including kidney disease, foot problems, blindness and heart disease. Yet more than 50 percent of adult diabetics do not meet the American Diabetes Association glycemic targets of less than seven percent AIC ¹ .

One reason for poor diabetes control is a failure to take sufficient insulin. This has been related to concern that insulin causes weight gain (which it does, but this is less detrimental to health than skipping insulin if you have type 1 diabetes). Women with eating disorders, such as anorexia, seem to be particularly preoccupied with this fear. And eating disorders seem to be more common among women with type 1 diabetes. Till now, there has been little research on the connection between insulin restriction and mortality in type 1 diabetes. Two studies, however, showed that adolescent and young women with both type 1 diabetes and anorexia had higher mortality rates than those with either condition alone ^2,3 . Another study showed that the use of insulin restriction as a way of calorie purging was linked to poor health outcomes ⁴ . Accordingly, a team led by the Joslin Diabetes Center in Massachusetts set out to follow up a group of women with type 1 diabetes to see what impact insulin restriction had on mortality rates and complications.

What was done

A total of 234 women (60 percent of the original group) with type 1 diabetes participated in this 11 year follow up study. Their mean age was 45 years and they had had diabetes for a mean time of 28 years. Mean body mass index was 25 and mean AIC 7.9 percent. At the start of the study (baseline) 30 percent of this group admitted insulin restriction. The researchers collected mortality data and asked the women whether they had suffered diabetes complications.

What was found

During the follow up period, 26 women died. Those who restricted their insulin had a 3.2 times increased risk of death compared to those who took insulin as instructed. Insulin restrictors died younger - at an average of 44 years compared to 58 years compared to those who did not restrict insulin. The mortality risk was directly related to the severity of insulin restriction. Forty percent of those who died compared to seven percent of those still living reported 'always' taking less insulin than they should. The insulin restrictors were more likely to be suffering from an eating disorder and had poorer self-reported levels of diabetes self-care compared to women who took insulin normally.

Insulin restrictors were more likely to report kidney complications - 25 percent versus ten percent - and foot problems - 25 percent versus 12 percent. However, there were no differences in rates of blindness or heart disease between women who did, and did not, restrict insulin.

What this study means

The researchers point out that this is the largest study to examine the long-term impact of insulin restriction on the morbidity and mortality of women with type 1 diabetes. The findings show that women who restrict insulin are putting themselves at risk of complications and even premature death. The habit appears to be part of an eating disorder, with these women using insulin restriction as a drastic weight loss tool.

Ideally, women suffering eating disorders and type 1 diabetes would receive in-depth evaluation and support from a mental health professional with a specialized training in diabetes. But such services are rarely available to these women. As a start, the researchers say, women with diabetes should be screened by capturing their response to the following statement 'I take less insulin than I should' to identify those who are at risk. Otherwise, lives will be lost because certain women with type 1 diabetes are tempted by the dangerous practice of insulin restriction.

Source

Insulin Restriction and Associated Morbidity and Mortality in Women with Type 1 diabetes
AE. Goebel-Fabbri, MA. Fikkan,  et al, Diabetes Care, 2008, vol. 31, pp. 415--419

Links

• Cognitive Ability and Diabetes
• Blood Sugar Predicts Cardiac Mortality

Footnotes

1.

A1C, also known as glycated hemoglobin, is a measure of blood glucose
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2.

Mortality in concurrent type 1 diabetes and anorexia nervose
JD. Walker, RJ. Young,  et al, Diabetes Care, 2002, vol. 25, pp. 1664--1665

3.

Mortality in concurrent type 1 diabetes and anorexia nervosa
S. Nielsen, C. Emborg,  et al., Diabetes Care, 2002, vol. 25, pp. 309--312

4.

The relationship of disordered eating habits and attitudes to clinical outcomes in young adult females with type 1 diabetes
RC. Peveler, KS. Bryden,  et al, Diabetes Care, 2005, vol. 28, pp. 84--88