Mission Statement
"The Illinois Department of Public Health was created in 1877 to regulate medical practitioners and to promote sanitation. Today, IDPH is responsible for protecting the state's 12.4 million residents, as well as countless visitors, through the prevention and control of disease and injury. The Department's nearly 200 programs touch virtually every age, aspect and cycle of life."

Examples of Recent Research Publications
Publications exist for a quite exhaustive list of diseases, injuries, harmful chemicals, and other public health issues this can be found on the organization's website here. These are mostly pdf files and are freely available to the public.

Data archives available
Chicago specific data and GIS maps are available from The Illinois Project for Local Assessment of Needs (IPLAN), a division of the IDPH.

Links
IDPH Main Page