Using PROC GLIMMIX and PROC SGPLOT to Demonstrate County-level Racial Disparities in Obesity in North Carolina


The agenda to reduce racial health disparities has been set primarily at the national and state levels. These levels may be too far removed from the individual level where health outcomes are realized. This disconnect may be slowing the progress in reducing these disparities. Behavioral Risk Factor Surveillance System data is used to estimate the prevalence of obesity by county among Non-Hispanic Whites and Non-Hispanic Blacks. A modified weighting system was developed based on demographics at the county-level, and a multilevel reweighted regression model using PROC GLIMMIX is fit to obtain county-level prevalence estimates by race. To examine whether racial disparities exist at the county-level, these rates are compared using risk difference and rate ratio. These county-level estimates are then compared graphically using PROC SGPLOT. The distribution of prevalence estimates for Blacks is shifted to the right in comparison to the distribution for Whites; based on a two-sample test for differences in proportions the mean of the distribution of obesity prevalence estimates for Blacks is 35.7% higher than for Whites in North Carolina. This difference is statistically significant (p<.0001). Addressing disparities based on factors such as race/ethnicity, geographic location, and socioeconomic status is a current public health priority. This study takes a first step in developing the statistical infrastructure needed to target disparities interventions and resources to the local areas with greatest need as well as providing a graphical representation of disparities, allowing for the implementation of interventions and dissemination of information to occur more effectively and efficiently.

Northeast SAS Users Group 2013