Changes in the availability of screening mammography, 2000-2010

Abstract

Background: Rates of screening mammography have plateaued, and the number of mammography facilities has declined in the past decade. The objective of this study was to assess changes over time and geographic disparities in the availability of mammography services.

Methods: Using information from the US Food and Drug Administration and the US Census, county-level mammography capacity was defined as the number of mammography machines per 10,000 women aged ≥ 40 years. Cross-sectional variation and longitudinal changes in capacity were examined in relation to county characteristics.

Results: Between 2000 and 2010, the number of mammography facilities declined 10% from 9434 to 8469, the number of mammography machines declined 10% from 13,100 to 11,762, and the median county mammography capacity decreased nearly 20% from 1.77 to 1.42 machines per 10,000 women aged ≥ 40 years. In cross-sectional analysis, counties with greater percentages of uninsured residents, less educated residents, greater population density, and higher managed care penetration had lower mammography capacity. Conversely, counties with more hospital beds per 100,000 population had higher capacity. High initial mammography capacity, growth in both the percentage of the population aged ≥ 65 years and the percentage living in poverty, and increased managed care penetration were all associated with a decrease in mammography capacity between 2000 and 2010. Only the percentage of rural residents was associated with an increase in capacity.

Conclusions: Geographic variation in mammography capacity and declines in capacity over time are associated with demographic, socioeconomic, and health care market characteristics. Maldistribution of mammography resources may explain geographic disparities in breast cancer screening rates.

Keywords: access; breast cancer; disparities; mammography; screening.

Figure 1. County mammography capacity and total mammography machines in the US, 2000-2010

Black circles indicate median county-level mammography capacity; gray bars indicate total number of mammography machines in all FDA-certified mammography facilities in each year.

Figure 2. Change in mammography capacity in all US counties, 2000-2010

The panel on the left shows the unweighted distribution of counties by change in mammography capacity over the study period. The panel on the right shows the distribution of counties by change in capacity weighted by county share of women age 40 and older. Change in capacity was estimated from the slope of a regression line for each county fit through capacity estimates in each year, 2000-2010. Counties with an increase (decrease) in capacity were defined by a positive (negative) estimated slope that was significantly different from 0 by t-test at a<0.05.