Eating disorders and diabetes
Individuals with type 1 diabetes (T1DM) are at particular risk of developing an eating disorder, the combination of which can lead to significant morbidity and mortality. Early detection and treatment is therefore essential.
There are currently four eating disorders commonly diagnosed in adults:
- anorexia nervosa,
- bulimia nervosa,
- binge eating disorder and
- eating disorder not otherwise specified.
Anorexia nervosa is characterised by extreme dietary restriction, such that individuals maintain a significantly low body weight. A sub-group of patients will also engage in driven exercise, self-induced vomiting, laxative misuse and/or binge eating. People with anorexia nervosa experience an intense fear of weight gain or becoming fat, even though significantly underweight. Body image distortion, feelings of fatness, and an extreme fear of uncontrolled weight gain are also common. Those with anorexia nervosa also tend to evaluate themselves almost exclusively in terms of their weight, shape and ability to control food. Anorexia nervosa is commonly regarded as being ‘egosyntonic’, as individuals are unable to recognise that there is anything wrong and have little insight into the seriousness of their low body weight.
Bulimia nervosa is characterised by two key features:
- recurrent episodes of binge eating, during which an objectively large amount of food is consumed with associated loss of control and;
- secondly, compensatory behaviours aimed towards the avoidance of weight gain. These may include self-induced vomiting, misuse of laxatives or diuretics, excessive exercise, or dietary restriction. People with bulimia nervosa commonly get stuck in a vicious cycle of dietary restriction, bingeing and purging. As with anorexia nervosa, those with bulimia nervosa evaluate themselves almost exclusively on the basis of weight, shape and ability to control food. People with bulimia nervosa tend to be of normal weight and most ‘value’ their symptoms less than those with anorexia nervosa, often bingeing and purging in secret.
Binge eating disorder
The key feature of binge eating disorder is regular episodes of binge eating. However, unlike those with bulimia nervosa, patients with binge eating disorder do not regularly engage in compensatory behaviours. Other key characteristics include eating much more rapidly than normal, eating until feeling uncomfortably full, and feeling disgusted with oneself after overeating.
Atypical eating disorders
Described as ‘atypical’ or ‘eating disorder not otherwise specified’ (EDNOS), this category consists of a number of sub-groups, a proportion of which comprise all but one of the key features of anorexia nervosa or bulimia nervosa. Other groups include those who chew and spit food rather than swallowing it, and those who purge after eating a small amount of food.
People with an eating disorder and T1DM may adopt the under-use or omission of insulin as a means of weight control leading to "self-induced glycosuria". The initial effect of this behaviour on body weight is rapid, chiefly as a result of water loss. Other eating disorder behaviours, such as strict dieting, binge-eating, vomiting, misuse of laxatives, and self-induced glycosuria are all likely to impair glycaemic control. In the short term, poor control may be manifest as recurrent symptoms of hyperglycaemia (e.g. thirst or tiredness), frequent episodes of ketoacidosis (often requiring hospital admission) or hypoglycaemia (leading to unconsciousness if severe). Growth retardation and pubertal delay may occur in prepubertal children. Evidence is now accumulating that patients with eating disorders are at considerably increased risk of physical complications of diabetes, including retinopathy, nephropathy or neuropathy , and that this is associated with high rates of physical morbidity and mortality.
The question of whether eating disorders are more prevalent in individuals with T1DM than in people without diabetes has been widely discussed. Given that both conditions are relatively common, they would be expected to co-occur by chance frequently. However, there are some theoretical reasons to expect eating disorders to be more common in the diabetic population. First, the non-specific stress of physical illness may increase the risk. Second, insulin therapy can lead to weight gain. Individuals with T1DM are likely to be heavier than their peers without diabetes and this can lead to increased body dissatisfaction and a stronger desire to lose weight. In addition, the availability of insulin under-use or omission as a means of weight control, the experience of rapid weight fluctuations around the time of diagnosis and the prescription of rigid dietary regimens may also serve as contributory risk factors.
A number of studies have explored the prevalence of eating disorders in those with T1DM. Results from two controlled studies suggest that rates of clinical eating disorders are not increased in the diabetic population, but this has not been supported by findings from a large multi-site study, which found that DSM-IV and sub-threshold eating disorders were about twice as common in adolescent females with T1DM as in their age-matched peers. Whilst it is not possible to be confident that anorexia nervosa and bulimia nervosa occur more frequently in people with T1DM, there is a strong suggestion that the prevalence of atypical eating disorders and sub-threshold cases may be increased.
Longitudinal studies have found disordered eating behaviour to be common and persistent in young women with T1DM, and associated with impaired metabolic control and increased risk of retinopathy. Results from an 8-year follow-up of adolescents with T1DM indicated a significant increase in body mass index from adolescence to young adulthood; and this was associated with a significant increase in body weight concern, shape concern, and dietary restraint. Findings from a follow-up study of young adults (aged 17-25 years at baseline) found that a quarter of the sample developed psychiatric morbidity and over one third microvascular complications of diabetes, indicating a poor prognosis for many young adults with T1DM in their 20s and 30s.
Early detection and treatment
Although some patients will volunteer information about eating disorder psychopathology, factors such as guilt and shame will lead many to be secretive about any problems they might have with their eating. However, there are a number of clinical characteristics that may suggest the presence of an eating disorder. Poor metabolic control, repeated episodes of hypoglycaemia or ketoacidosis and weight fluctuations are important indicators of risk and their presentation should prompt sensitive but direct questioning relating to eating habits and attitudes, concerns about body weight and methods of weight control. The potential for eating disturbance should be borne in mind particularly when working with those most at risk, namely adolescent and young adult females. The use of standardised measures such as the revised Diabetes Eating Problem Survey alongside a clinical interview can also facilitate screening and encourage discussion of eating concerns and behaviours that might impair diabetes management.
Treatment is best delivered through a multi-disciplinary team, and should involve both diabetic management and mental health treatment. Whilst the diabetes team and the eating disorder team will have separate responsibilities, it is essential that they work collaboratively. Only if good communication can be established and maintained is treatment likely to be optimal.
Type 2 Diabetes
The peak incidence of eating disorders occurs in adolescence and young adulthood, and such disorders are therefore most likely to occur in combination with Type 1 diabetes. However, some clinical features of disordered eating can persist into middle and later life, and may be seen in people with Type 2 diabetes. Binge eating disorder, in particular, is often associated with obesity and is the most likely condition to occur in this patient population. As it may be susceptible to psychological treatment, and may necessitate a departure from the usual dietary advice given to patients, it is good practice for clinicians to enquire about current or past binge eating episodes when assessing overweight or obese people with Type 2 diabetes.
^ American Psychiatric Association (2013). Diagnostic and Statistical Manual of Mental Disorders (DSM-V), 5th edition, Washington DC: APA Press.
^ Peveler, R. C., Bryden, K., Neil, H. A. et al. (2005). The Relationship of Disordered Eating Habits and Attitudes to Clinical Outcome in Young Adult Females With Type 1 Diabetes. Diabetes Care, 28, (1), 84-88.
^ Nielson, S. (2002). Eating Disorders in Females with Type 1Diabetes: An Update of a Meta-analysis. European Eating Disorders Review, 10, 241–254.
^ Fairburn, C. G., Peveler, R. C., Davies, B. A., Mann, J. I., & Mayou, R. A. (1991). Eating Disorders in Young Adults With Insulin Dependent Diabetes: a Controlled Study. British Medical Journal, 303:17-20.
^ Peveler, R. C., Fairburn, C. F., Boller, I., & Dunger, D. (1992). Eating Disorders in Adolescents With Insulin-Dependent Diabetes Mellitus. Diabetes Care 10:1356-60.
^ Jones, J. M. Lawson M. L. Daneman D. Olmsted M. P. & Rodin G. (2000). Eating Disorders in Adolescent Females With and Without Type 1 Diabetes: Cross Sectional Study. British Medical Journal, 320:1563-6.
^ Rydall, A. C., Rodin, G. M., Olmsed, M. P., Devenyi, R. G., & Daneman, D. (1997). Disordered Eating Behavior and Microvascular Complications in Young Women With Insulin-Dependent Diabetes Mellitus. The New England Journal of Medicine, 336(26), 1849-54.
^ Bryden, K. S., Neil, H. A., Mayou, R. A., Peveler, R. C., Fairburn, C. F., & Dunger, D. (1999). Eating Habits, Body Weight, and Insulin Misuse. A Longitudinal Study of Teenagers and Young Adults With Type 1 Diabetes. Diabetes Care,; 22(12):1956-60.
^ Bryden, K. S., Dunger, D., Mayou, R. A., Peveler, R. C., and Neil, H. A. (2003). Poor Prognosis of Young Adults With Type 1 Diabetes: A Longitudinal Study. Diabetes Care, 26(4):1052-7
^ Markowitz, J.T., Butler, D.A., Volkening, L., Antisdel, J.E., Anderson, B.J., Laffel, L. (2010). Brief Screening Tool for Disordered Eating in Diabetes:Internal consistency and external validity in a contemporary sample of pediatric patients with type 1 diabetes. Diabetes Care, 33, 495-500