We already know that there are many risk factors linked to type 2 diabetes. These include dietary and lifestyle factors, environment, and tiny substances in the blood (known as biomarkers, such as markers of inflammation). We are not sure if these risk factors cause diabetes, or if they just occur together with diabetes at the same time by chance. To answer this question, researchers used genetic profiles from 900,000 participants of European descent. Nineteen factors appear to directly contribute to causing type 2 diabetes, including depression, smoking, caffeine consumption, obesity as a child or adult and a high systolic blood pressure. Insomnia (a sleep disorder) is a new risk factor directly linked to causing type 2 diabetes. We already know the importance of avoiding excess weight gain for people at risk of type 2 diabetes. This new study suggests that other prevention strategies are just as important, including reducing smoking, improving mental health, and improving sleep quality.