Every year, the CDC collects behavioral health risk data via telephone surveys at the state and local level. The Behavioral Risk Factor Surveillance System (BRFSS) produces a powerful public data set for analyzing geographic trends in population health.
This layered choropleth presents four factors associated with Diabetes: the prevalence of Diabetes, the prevalence of Depression, a major comorbidity; the presence of health eating behavior; and the presence of non-employment exercise. At the top, each layer, presented as a map of the 48 contiguous states, is shaded a different color based on the percentage of the population that meet the survey criteria for one of the four factors above. At the bottom, those four choropleths are overlaid and the resulting colors merged, revealing the dominant health challenges facing each state.
For example, the Northwest and Northeast states are mostly teal, indicating that they have healthy behaviors but suffer depression more than most other states. Many non-coastal southern and Midwestern states, such as Tennessee, West Virginia, and Oklahoma, have multiple overlapping health challenges and are shaded deep red or even black. Colorado, Nevada, Utah, Minnesota and Illinois stand out as being among the healthiest states.
D3.js SVG, with Illustrator
Data from CDC Behavioral Risk Factor Surveillance System (BRFSS)