Among 175,112 Dutch adults with type 2 diabetes followed in the DIAMANT primary care cohort, striking ethnic disparities emerged in complication risk profiles. Retinopathy hazard ratios ranged 1.37–2.37 higher across nearly all non-Dutch ethnic groups. Surinamese and Turkish individuals faced elevated heart failure risk (HRs 1.30 and 1.46 respectively), while Indonesian and Moroccan-origin patients showed similar or reduced macrovascular risk versus Dutch-origin individuals. Machine-learning variable selection identified air pollution, ambient temperature, welfare dependency, and household composition as substantial mediators, collectively explaining a meaningful proportion of these ethnic disparities.
This large-scale analysis adds important nuance to a well-documented global phenomenon: ethnic minority populations consistently bear heavier T2D complication burdens. Most prior research has attributed these gaps primarily to clinical factors like glycemic control or BMI. This study's strength lies in explicitly quantifying environmental and socioeconomic mediators — a relatively underexplored pathway — in a cohort of exceptional size. The finding that retinopathy risk is elevated across virtually all minority groups suggests clinical pathways may dominate there, while macrovascular disparities appear more environmentally and socially modifiable. For clinicians, this signals that complication screening protocols may need ethnic-specific calibration. For policymakers, targeting air quality and poverty reduction could plausibly reduce diabetes complication burdens. Important limitations include the observational design precluding causal inference and potential residual confounding. As a preprint not yet peer-reviewed, these findings should be interpreted cautiously until formal review validates the analytical approach.