Description of the research
What was the goal of your research?
We wanted to learn more about how type 2 diabetes and brain disorders are associated with each other. Brain disorders can be mental disorders (such as depression, schizophrenia or ADHD), or neurological disorders (such as inflammatory brain diseases and epilepsy). Moreover, we wanted to examine whether these links depended on which of the two disorders, type 2 diabetes or the brain disorder, people were diagnosed with first.
How did you measure or test this?
We used Danish population-based register data including 1.9 million individuals born between 1955 and 1984. First, we estimated pairwise associations between type 2 diabetes and 16 brain disorders, regardless of which one of the two was diagnosed first. Second, we estimated the risk of developing type 2 diabetes if someone has previously been diagnosed with a brain disorder, compared with those without such a prior disorder. In the third step we did the reverse: we estimated the risk of having a brain disorder, depending on whether or not an individual had a prior diagnosis of type 2 diabetes.
What were the main results or findings?
Overall, we found that type 2 diabetes was linked with an increased risk of most of the psychiatric and neurological disorders. These links were consistently found in both directions, except for anorexia nervosa and amyotrophic lateral sclerosis (ALS). Strongest associations with type 2 diabetes were seen for psychiatric disorders, particularly non-anorectic eating disorders and schizophrenia spectrum disorder.
What does this mean?
Our findings emphasize the importance of monitoring people with type 2 diabetes as a high-risk group for mental health problems. Similarly, psychiatrists should be aware that patients with a mental disorder have an increased risk to develop type 2 diabetes. Both strategies could improve early identification and treatment of mental disorders and type 2 diabetes, respectively.
What is the next step?
The current study is observational, which means that we can’t say anything about what causes this overlap in risks. Future studies should aim to identify the underlying causal mechanisms. This can be studied using a range of different methodologies, such as genetic epidemiology, molecular genomics, and animal research, some of which are currently applied by partners within the PRIME research consortium in ongoing studies.
- PRIME research publication: Insulinopathies of the brain? Genetic overlap between somatic insulin-related and neuropsychiatric disorders
Title: Temporally ordered associations between Type 2 Diabetes and Brain Disorders – a Danish Register-Based Cohort Study
Authors: Theresa Wimberley, Henriette T. Horsdal, Isabell Brikell, Thomas M. Laursen, Aske Astrup, Giuseppe Fanelli, Janita Bralten,Geert Poelmans,Veerle Van Gils,Willemijn J. Jansen,Stephanie J. B. Vos,Valérie Bertaina-Anglade,Lucia Camacho-Barcia, Bernat Mora-Maltas, Fernando Fernandez-Aranda, Mònica B Bonet, Jordi Salas-Salvadó, Barbara Franke, Søren Dalsgaard
Journal: BMC Psychiatry