Diabetes diagnoses in the U.S. continue to rise, bringing with them additional complications that are sometimes disabling or even life-threatening. Those complications can include cardiovascular disease, nerve damage, kidney damage, eye damage and other conditions.
Louisville currently ranks 14th among its peer cities in the percent of adults who are 20 and older who have been diagnosed with diabetes.
Louisville is in the bottom tier of its peer group according to a natural breaks algorithm. Cities in green are those that outperform their peers. Cities in yellow represent the middle cluster, and those in red lag behind their peers on this indicator.
Since 2004, the percent of the adult population diagnosed with diabetes has increased, though it is now increasing at a slower rate than it was two decades ago. Louisville generally followed the trend of its peer cities until the early 2010s, at which point it started to diverge and recorded higher shares of diabetes diagnoses.
Louisville and all of its peer cities have recorded higher rates of diabetes since 2004. Overall, the diabetes rate has risen the most in Birmingham, at about 4 percentage points. Meanwhile, in Charlotte, the best performer, the diabetes rate rose by 1.5 percentage points.
In Louisville, the diabetes rate among men and women largely moved in tandem for much of the last two decades. However, recently, the female diabetes rate has increased more sharply than the male diabetes rate. It now sits at 10.8%, compared with 11.2% for men.
For each indicator, Greater Louisville Project assigns cities into one of three groups (high-performing, middle-of-the-pack, and low-performing) based on how they compare to other cities. The assignment is based on how cities naturally cluster on that indicator. Sometimes, the differences between cities are very small, and the difference between a city ranked 5th and 6th could simply be a matter of the sampling error that arises from using survey data. Thus, rather than always make a division that declares the top 5 to be the top tier, we use a natural breaks algorithm to look for a cluster of cities that is outperforming the rest, a cluster that is about average, and a cluster that is lagging. This clustering gives us a better indication of where Louisville is thriving and where Louisville has room to learn from cities that are doing better.
Z-scores (or standardization) is a way to combine data with different units of measurement into a single index. The z-score is a measure of how far away a city (or census tract, etc.) is from the average city. In order to be comparable across different units of measurement, the z-score is the distance from the mean measured in standard deviations (e.g. if Louisville has a z-score of 1 it means Louisville is 1 standard deviation above the mean of its peer cities).
Data from the Robert Wood Johnson Foundation's County Health Rankings use z-scores and all z-scores are relative to the mean of Louisville's peer cities. (On the County Health Rankings site z-scores are relative to all the counties in each state - thus z-scores reported by GLP will be different, because we are using a different reference group). The Greater Louisville Project also uses z-scores in our multidimensional poverty index, which compares each census tract to the mean of all census tracts in Louisville.
