Anorexia nervosa related to type 2 diabetes mellitus in an elderly woman: a case report

Abstract

Although eating disorders (EDs) are more common in young women, the incidence of EDs in elderly patients is increasing. However, even though the occurrence of these disorders in the elderly has been reported, their pathogenesis has not been sufficiently clarified. In this report, we present a case of an elderly woman who developed anorexia nervosa (AN) believed to be related to the onset of type 2 diabetes mellitus. This report conformed to the rules of the Ethics Committee of Fukushima Medical University Hospital, and to the provisions of the Declaration of Helsinki. The patient was a 72-year-old Japanese woman. She was an only child. After graduating from a local high school, she worked for a sewing company. She got married in her thirties and had a child. After her marriage, she retired and became a housewife. She lived with her husband and son; their relationships were not bad. Although she had always been a nervous person, she had never visited a psychiatrist before. She had never been diagnosed with an ED in the past but was diagnosed with type 2 diabetes mellitus 10 years ago and treated with medications. Although her haemoglobin A1c level was generally stable at approximately 7%, she became concerned about her diabetes mellitus and began to restrict her calorie intake. Her initial body mass index (BMI) was approximately 22. However, because of her sustained dietary restrictions, her BMI decreased to approximately 15. Although her family was worried about her weight loss, she did not stop her extreme dietary restriction because she was concerned about weight gain and worsening her diabetes. These eating behaviours started at the age of 67. Initially, her fear and anxiety about her diabetes were prominent, which however declined gradually. Afterwards, she rather developed a fear of obesity, a distorted view of her body image, and a significant avoidance of fattening foods—which were later characterized as AN. She underwent a medical examination at the Department of General Internal Medicine and was diagnosed with a markedly low body weight and electrolyte abnormalities due to decreased food intake. Blood sampling and magnetic resonance imaging of her whole body did not show any other abnormal findings. She was then admitted to our hospital because of significant weight loss to the point where her BMI had dropped to 12.1. After hospitalization, the patient refused to eat because of fear of weight gain. She showed no symptoms of depressed mood, pessimism, or loss of interest. Her Mini-Mental State Examination score was 27. She also showed no signs of progressive cognitive decline that would indicate dementia. However, she showed marked weight loss, restriction of food intake, disturbance of her own body image, and fear of obesity. Contrarily, she did not exhibit overeating, self-induced vomiting, or the misuse of laxatives or diuretics. Therefore, she was diagnosed with the restricting type of AN according to criteria in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition. Although weight gain was eventually achieved through tube feeding, she was still unable to consume any food and was eventually admitted into social welfare facilities where tube feeding was maintained. To the best of our knowledge, this is the first report of type 2 diabetes mellitus related to the development of AN in an elderly patient. The relationship between diabetes mellitus and EDs is well known. Type 1 diabetes significantly increases the incidence of EDs in young women. Moreover, type 2 diabetes is mainly associated with binge EDs and secondary depression. In the present case, the patient showed no signs of depression or decreased motivation associated with depression. However, she showed loss of appetite based on an intense fear of gaining weight. Takii et al. speculated that the psychosocial burden of having