No Drop in Mammograms Here: What makes the Golden State Exceptional?

Recent estimates from the National Health Interview Survey (NHIS) showed the first decline in mammography use since 1987. National rates dropped from 70% to 66% between 2003 and 2005. We examine whether mammography use dropped in California.

We used the California Health Interview Survey (CHIS) to examine recent mammography use among women 40 and older between 2003 and 2005. Recent use is defined as having a mammogram within two years prior to interview. The study population of women 40 and older is 16,629 in 2003 and 18,545 in 2005. Differences in recent mammography use are presented for a range of characteristics and tested for statistical significance. To confirm the increase in mammography after controlling for other variables, data on women 40-79 years old were pooled and logistic regression analysis performed to ascertain the adjusted rates of change.

We present county and state estimates of mammography for California. Unlike findings for mammography for the nation as a whole, California rates rose slightly between 2003 and 2005, from 76% to 78%. In addition to the 2 percentage point increase statewide, rates increased 4 percentage points in Los Angeles County, 5 percentage points in San Diego and 10 percentage points in San Francisco. Statewide increases were found among some groups of women who had lower mammography rates in 2003. Mammography rates increased for women regardless of whether they saw a doctor in the past 12 months, but especially for women who had not visited a doctor (14.1 percentage points). This slightly narrowed the gap in mammography rates between these groups. The large increase in mammography among women 65 and older with non-HMO Medicare coverage similarly reduced the disparity for this age group.

California's provisions for breast cancer screening, diagnosis and timely treatment for the uninsured, a widespread system of health maintenance organizations, and regulated health insurance market may help explain both the overall increase in mammography use and reduced disparities in mammography use that occurred between 2003 and 2005. CHIS enables counties to track, evaluate and take corrective action to improve mammography use.

California's combination of insurance regulation, organized screening programs and regular monitoring of outcomes at the county level has led to an increase in mammography service levels. This is in contrast to the nation as a whole which does not share these characteristics. This analysis demonstrates the value of state and local survey data to inform health policy, delivery and practice.