Researchers have long understood that having certain diseases, like diabetes, increases your risk for having other diseases, like high blood pressure.

Now a team of researchers from Northeastern University and Harvard University has created a map that visually shows these “disease associations” in a sample of more than 30 million people. Built from data included in insurance claims, the map—called the Phenotypic Disease Network—is the largest disease-network database ever built.

The map has been made publicly available at an interactive website (http://hudine.neu.edu), which even allows site visitors to compare the strength of specific disease associations shown by men and women of different ethnicities.

Experts believe that studying linkages like these could greatly expand medical knowledge. According to study co-author Albert-László Barabási, distinguished professor of physics and director of Northeastern’s Center for Complex Network Research, examining disease associations may be “a viable path toward elucidating the origins of specific diseases.”

“Mapping disease networks using digital medical records dramatically changes the way we understand diseases in general,” said César Hidalgo, researcher at Harvard University’s Center for International Development and lead author of the study. “Disease networks can also be used to inform patients of diseases they may be at risk of developing. This opens new potential applications and opportunities for digital medical records.”

The team’s findings have been published in a paper titled “A dynamic network approach for the study of human phenotypes,” which appears in the current issue of the journal “Public Library of Science (PLoS) Computational Biology.”

Among other results, the researchers also found that patients affected by diseases connected to other diseases tend to die sooner than those affected by less-connected diseases.