German Diabetes Center
For most of medical history, diabetes mellitus came in two flavors: type 1 and type 2. Then, in 2019, a team from the German Diabetes Center in Dusseldorf, working with partners at the University of Lund, published a study in the Lancet that broke the disease into five distinct clusters - each with its own complication risks, its own progression, its own implications for treatment. People with severe insulin-resistant diabetes turned out to be the most likely to develop non-alcoholic fatty liver disease. People with severe insulin-deficient diabetes faced the highest risk of nerve damage. The familiar binary diagnosis suddenly looked like a rough sketch. The work continues from a research center founded almost by accident, in 1964, by a German doctor named Karl Oberdisse who refused to accept the standard of diabetes care in his own country.
An Association for the Promotion of Research
The DDZ - Deutsches Diabetes-Zentrum - began in 1964 as the Association for the Promotion of Research on Diabetes mellitus, a clunky name in any language. Professor Karl Oberdisse, an internal medicine specialist who saw the country's diabetes care lagging behind its industrial recovery, organized the founding. Six decades later the institute is a Leibniz Center for Diabetes Research, an affiliated institute of Heinrich Heine University, and a member of the Leibniz Association - the federation of German non-university research institutes named for the seventeenth-century polymath. Its legal body is still the Deutsche Diabetes-Forschungsgesellschaft. Around 240 employees work across institutes for Clinical Diabetology, Metabolic Physiology, Vascular and Islet Cell Biology, Biometrics and Epidemiology, and Health Services Research. Half the funding comes from the German Federal Ministry of Health, half from the North Rhine-Westphalia Ministry of Culture and Science, with project funding layered on top from the European Union, the German Research Foundation, and the federal education ministry.
The Five-Cluster Study
The German Diabetes Study began enrolling participants more than a decade ago and now follows about 1,500 people from the moment they receive a diabetes diagnosis through at least ten years of follow-up. It measures metabolic changes within the first year. It tracks comorbidities and late effects. It maintains tissue samples and detailed phenotyping that few other diabetes cohorts in the world can match. The 2019 Lancet paper that emerged from this work - lead author Oana Zaharia, with Michael Roden as senior author - identified five subtypes of recent-onset diabetes that did not align cleanly with the old type-1/type-2 division. Some patients with what looked like type 2 actually had immune markers more characteristic of type 1. Others had severe insulin resistance without the obesity profile clinicians typically associate with it. The clusters predicted, with statistical clarity, who would develop fatty liver disease and who would lose nerve function. The concept of precision medicine - matching treatment to the specific underlying disease, not the broad label - found its proof of concept here.
Sixty-Five Million Records
Other DDZ work runs at a different scale. Professor Wolfgang Rathmann and his group built models drawing on data from approximately 65 million people with German statutory health insurance plus records from the Federal Statistical Office, projecting how the number of type 2 diabetes cases in Germany is likely to evolve through coming decades. The work produced a web tool called the Diabetes Watch, which shows prevalence and incidence in Germany in something close to real time. Since 1989 the DDZ has maintained a population-based diabetes incidence register specifically for childhood, adolescence, and young adulthood, a long-running dataset that lets researchers see how onset patterns are changing in the youngest patients. The institute participates in the Europe-wide EURODIAB ACE collaboration on type 1 diabetes epidemiology, and runs a study center for the NAKO Gesundheitsstudie - the German National Cohort, which is examining 200,000 Germans for clues to preventing cancer, dementia, and diabetes itself.
The Liver, the Heart, the Beta Cell
Diabetes does not stay in one organ. Cardiovascular disease drives much of the excess mortality in diabetic patients, and DDZ scientists - Michael Roden again, with Julia Szendrodi - have spent years inside SFB 1116, a collaborative research center funded by the German Research Foundation, looking for what they call master switches for cardiac ischemia: the molecular controls that determine whether a heart muscle starved of blood survives or dies. The Lammert group has illuminated how the liver regenerates and what goes wrong in fatty liver disease, including a 2018 Nature paper showing that mechanical sensing by beta-1 integrin triggers angiocrine signals essential for liver growth. The Al-Hasani group runs the vivid Research Training Group studying the earliest changes that favor type 2 diabetes, before the disease appears. Since 2018, KomIT - the Competence Center for Innovative Diabetes Therapy - has coordinated industry and university partners to translate research into clinical use. Every year, since 2016, the institute awards the Von Mering Medal, named for the nineteenth-century German physiologist Josef von Mering whose work with Oskar Minkowski established that the pancreas controls blood sugar - the discovery that made everything else possible.
From the Air
The DDZ sits on the Heinrich Heine University campus in southern Dusseldorf at 51.20 degrees north, 6.79 degrees east. The university campus is the dominant landmark - a cluster of modern academic buildings south of the city center, with the University Hospital Dusseldorf adjacent. The Rhine bends past the city to the west. Dusseldorf Airport (ICAO EDDL) is 12 km north.