Mammograms on-the-go—predictors of repeat visits to mobile mammography vans in St Louis, Missouri, USA: a case–control study

OBJECTIVES: Among women, breast cancer is the most common non-cutaneous cancer and second most common cause of cancer-related death. The purpose of this study was to determine the extent to which women use mobile mammography vans for breast cancer screening and what factors are associated with repeat visits to these vans. DESIGN: A case–control study. Cases are women who had a repeat visit to the mammography van. (n=2134). PARTICIPANTS: Women who received a mammogram as part of Siteman Cancer Center's Breast Health Outreach Program responded to surveys and provided access to their clinical records (N=8450). Only visits from 2006 to 2014 to the mammography van were included. OUTCOME MEASURES: The main outcome is having a repeat visit to the mammography van. Among the participants, 25.3% (N=2134) had multiple visits to the mobile mammography van. Data were analysed using χ(2) tests, logistic regression and negative binomial regression. RESULTS: Women who were aged 50–65, uninsured, or African-American had higher odds of a repeat visit to the mobile mammography van compared with women who were aged 40–50, insured, or Caucasian (OR=1.135, 95% CI 1.013 to 1.271; OR=1.302, 95% CI 1.146 to 1.479; OR=1.281, 95% CI 1.125 to 1.457), respectively. However, the odds of having a repeat visit to the van were lower among women who reported a rural ZIP code or were unemployed compared with women who provided a suburban ZIP code or were employed (OR=0.503, 95% CI 0.411 to 0.616; OR=.868, 95% CI 0.774 to 0.972), respectively. CONCLUSION: This study has identified key characteristics of women who are either more or less likely to use mobile mammography vans as their primary source of medical care for breast cancer screening and have repeat visits.