Type 2 diabetes and chronic gastritis/duodenitis comorbidity: additive risk for incident depression and synergistic risk for all-cause mortality – a retrospective cohort study

Background Type 2 diabetes (T2D) and chronic gastritis/duodenitis (CGD) are both associated with the onset of depression and mortality. However, the impact of T2D-CGD comorbidity on incident depression and mortality remains unclear.

This retrospective cohort study utilized data from 387,149 participants in the UK Biobank to examine the relationship between T2D-CGD comorbidity, incident depression, and all-cause mortality. Outcome Patients with T2D are more likely to develop CGD compared to those without T2D (odds ratio = 2·10, 95% CI = [1·97, 2·24]). T2D, CGD, and their comorbidity each independently increased risks of depression incidence and all-cause mortality, with T2D-CGD showing the strongest associations for both (depression incidence: adjusted hazard ratio [aHR] = 2·29, 95% CI = [1·84, 2·85]; all-cause mortality: aHR = 2·57, 95% CI = [2·28, 2·88]). The synergistic effect of T2D and CGD on all-cause mortality was 1·92 times that of their individual effects combined (synergy index = 1·92, 95% CI = [1·56, 2·31]). The comorbidity was associated with a higher risk of depression and all-cause mortality within 15 years of disease onset. White matter hyperintensity, particularly near the cerebral ventricles, partially mediated the relationship between T2D-CGD comorbidity and incident depression. Interpretation Integrated screening and long-term monitoring strategies should be prioritized for population with the comorbidity of T2D and CGD, as it significantly elevates the risk of both incident depression and all-cause mortality. Competing Interest Statement The authors have declared no competing interest. Funding Statement BH has received funding from the National Natural Science Foundation of China [grant number 82302148]. YY has received funding from the Key Science and Technology Program of Shaanxi Province [grant number 2023-YBSF-331] and Fourth Military Medical University [grant number 2023XC045]. GBC has received funding from the National Natural Science Foundation of China [grant number 82471936]. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study used ONLY openly available human data that were originally located at UK Biobank. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes