Multilevel Small-Area Estimation of Colorectal Cancer Screening in the United States

Background: The U.S. Preventive Services Task Force recommends routine screening for colorectal cancer for adults ages 50 to 75 years. We generated small-area estimates for being current with colorectal cancer screening to examine sociogeographic differences among states and counties. To our knowledge, nationwide county-level estimates for colorectal cancer screening are rarely presented.

Methods: We used county data from the 2014 Behavioral Risk Factor Surveillance System (BRFSS; n = 251,360 adults), linked it to the American Community Survey poverty data, and fitted multilevel logistic regression models. We post-stratified the data with the U.S. Census population data to run Monte Carlo simulations. We generated county-level screening prevalence estimates nationally and by race/ethnicity, mapped the estimates, and aggregated them into state and national estimates. We evaluated internal consistency of our modeled state-specific estimates with BRFSS direct state estimates using Spearman correlation coefficients.

Results: Correlation coefficients were ≥0.95, indicating high internal consistency. We observed substantial variations in current colorectal cancer screening estimates among the states and counties within states. State mean estimates ranged from 58.92% in Wyoming to 75.03% in Massachusetts. County mean estimates ranged from 40.11% in Alaska to 79.76% in Florida. Larger county variations were observed in various race/ethnicity groups.

Conclusions: State estimates mask county variations. However, both state and county estimates indicate that the country is far behind the "80% by 2018" target.

Impact: County-modeled estimates help identify variation in colorectal cancer screening prevalence in the United States and guide education and enhanced screening efforts in areas of need, including areas without BRFSS direct-estimates. Cancer Epidemiol Biomarkers Prev; 27(3); 245–53. ©2018 AACR.

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