Diabetes seems to be one of the main causes of heart disease.

> People with diabetes tend to develop heart disease at a younger age than people without diabetes. In adults with diabetes, the most common causes of death are heart disease and stroke. Adults with diabetes are nearly twice as likely to die from heart disease or stroke as people without diabetes [0]

[0] https://www.niddk.nih.gov/health-information/diabetes/overvi...

[1] "What if Heart Disease and Diabetes had the same cause?" https://www.youtube.com/watch?v=ofq-8ToY2fc