County-Level Factors Predicting Low Uptake of Screening Mammography.

OBJECTIVE: The purpose of this study was to investigate county-level geographic patterns of mammographic screening uptake throughout the United States and to determine the impact of rural versus urban settings on breast cancer screening uptake.

MATERIALS AND METHODS: This descriptive study used County Health Rankings data to identify the percentage of Medicare enrollees 67-69 years old per county who had at least one mammogram in 2013 or 2012 (uptake). Uptake was matched with U.S. Department of Agriculture Atlas of Rural and Small Town America categorizations along a rural-urban continuum scale from 1 to 9 based on county population size (large urban, population ≥ 20,000 people; small urban, < 20,000 people) and proximity to a metropolitan area. Univariable and multivariable analyses were performed.

RESULTS: In all, 2,243,294 Medicare beneficiaries were eligible for mammograms. National mean uptake per county was 60.5% (range, 26.0-86.0%). Uptake was significantly higher in metropolitan and large urban counties in 25 states and lower in only one. County-level mammographic uptake was moderately positively correlated with percentage of residents with some college education (r = 0.40, p < 0.001) and moderately negatively correlated with age-adjusted mortality (r = -0.41, p < 0.001). Multivariable analysis showed that percentage of white and black residents and age-adjusted mortality rate were the strongest significant independent predictors of uptake.

CONCLUSION: Uptake of mammographic screening services in a Medicare population varies widely at the county level and is generally lowest in rural counties and urban counties with fewer than 20,000 people.