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

Abstract

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.

Conflict of interest statement

Conflict of interest: No potential conflicts of interest exist

©2018 American Association for Cancer Research.

Figures

Figure 1

Model-based county estimated prevalence (%) maps for being current with 3 CRC test types. The maps show estimated prevalence for (A) any CRC test type, (B) Colonoscopy within 10 years, and (C) FOBT within the past year. Any CRC test type (A) includes FOBT within the past year; sigmoidoscopy within 5 years with FOBT within 3 years; or colonoscopy within 10 years. The County prevalence shown on the right of each map describes the prevalence by quintiles, each associated with a different color scale. Notes: CRC, colorectal cancer; FOBT, Fecal occult blood test