In large international sample of patients with mental disorders, binge eating disorder and bulimia nervosa were found to have an even stronger association with diabetes than other disorders….
Previous studies have found that depression and diabetes frequently occur together, and that depression may serve as a risk factor for diabetes. Furthermore, it is thought that treatment of depression may decrease the risk of developing diabetes later in life. Previous studies on this topic used sample populations from the United States and Europe, limiting the generalizability of their findings to other countries. Also, as these previous studies did not collect reliable data on mental disorders other than depression, it is unclear as to whether the depression-diabetes association may actually be due to the presence of other mental disorders. A new study conducted by de Jonge, P. et al. was designed to investigate the association between mood, anxiety, impulse control and substance use disorders with diagnosis of diabetes in a large international sample. This study also planned to evaluate whether focus on depression alone as a risk factor for diabetes is warranted by conducting analyses with and without adjustment for mental disorder comorbidity.
The study was conducted using data from the World Mental Health surveys of 19 different countries. For data collection regarding mental disorders, an interview was conducted by trained laypersons to assess the lifetime history of most mental disorders. A total of 16 mental disorders were assessed, and include: anxiety disorders, mood disorders (MDD/dysythmia, bipolar disorder), impulse control disorders (intermittent explosive disorder, bulimia nervosa, binge eating disorder), and substance use disorders (alcohol and drug). For data collection regarding diabetes mellitus, a series of questions adapted from the US Health Interview Survey were used to ask the patients about the lifetime prevalence and age of onset of selected chronic conditions. Only adult onset diabetes was studied (onset at 21 years or older). Patient with mental disorders first occurring in the same year of diabetes diagnosis or following diabetes diagnosis were excluded.
Major depression, specific phobia, and alcohol abuse were found to be the most prevalent mental disorders in this group. All mental disorders were found to be associated with diabetes except for OCD. Binge eating disorder and bulimia nervosa were found to have an even stronger association with diabetes than the other disorders. Multivariate models were then used to account for lifetime comorbidity until the age of diabetes onset. This significantly decreased the magnitude of the associations found for most of the disorders, leaving only 4 of the 16 mental disorders having a significant association with diabetes diagnosis. These 4 disorders include: major depressive episode/dysythmia, intermittent explosive disorder, binge eating disorder and bulimia nervosa.
There are several limitations to this study that limit the usefulness of its findings. As this was a retrospective study, there may have been under-reporting of the mental disorders and reports regarding age of onset may be inaccurate. This study also only included living patients with diabetes and mental disorders, so people that have already died of these conditions, and may have had the strongest association of all, were not assessed. Type 1 and type 2 diabetes were were not differentiated in this study, though most patients were likely type 2 as participants were required to be at least 21 when they were diagnosed with diabetes. Another limitation is that this study only looked at 16 mental disorders, and therefore the findings cannot be applied to other mental disorders not included in the analysis.
In conclusion, the results of this study in regards to depression were consistent with results from previous meta-analyses. In adjusted analyses, depression resulted in a 30% increased risk of diabetes, showing that association between diabetes and depression is relatively independent of other mental disorders. Of the mental disorders studied, eating disorders were found to have the strongest association with diabetes. This makes sense when one thinks about how eating disorders affect obesity and glucose regulation. Further research, however, is needed to explore these associations and their mechanisms in greater depth.
- Binge eating disorder and bulimia nervosa were found to have the strongest association with onset of diabetes.
- Focus on the treatment of depression and impulse control disorders may help to reduce risk of diabetes diagnosis.
de Jonge, P. et al. "Associations between DSM-IV mental disorders and diabetes mellitus: a role for impulse control disorders and depression" Diabetologia. 2014.