Association between anorexia nervosa and type 2 diabetes in Sweden: Etiological clue for the primary prevention of type 2 diabetes.

AIM: Caloric restriction has been found to be protective against the development of type 2 diabetes mellitus (T2D) in experimental animal studies. However, studies examining this association in humans are limited. In the present study, we examined whether individuals with anorexia nervosa, one marker of severe caloric restriction in humans, have a low incidence of T2D by using several Swedish registries.

METHODS: Individuals with anorexia nervosa were identified from the Swedish Hospital Discharge Register and Outpatient Register between 1964 and 2010. Standardized incidence ratios (SIRs) for T2D were studied among individuals with anorexia nervosa compared to those without the disorder.

RESULTS: A total of 17,135 individuals were identified with anorexia nervosa in Sweden. From this tally, 34 of them developed T2D, demonstrating a reduced risk of T2D with a SIR of 0.70, compared to individuals without anorexia nervosa. Patients with severe anorexia, indicated by more frequent hospitalizations, had a statistically non-significant lower incidence of T2D than those with fewer hospitalizations. A sibling study, controlled for familial confounding, found a statistically non-significant association between anorexia nervosa and T2D.

CONCLUSION: Our study found that severe caloric restriction by using individuals with anorexia nervosa as a proxy was negatively associated with T2D, which might provide a biological basis for the primary prevention of T2D. Further studies are needed to explore whether moderate caloric restriction can effectively prevent the development of T2D in general population.