Breast cancer screening use in women older than 40 years depends on the health system, primary care visits, median household income, and health insurance type, according to a cohort study involving more than 3,400 individuals.

Participants were from either Brigham and Women's Hospital or Geisel School of Medicine at Dartmouth. Investigators looked for time to first breast cancer screening, cohort exit, or 42nd birthday. Among the results:

• Nearly two-thirds of patients at Brigham were screened, vs 4 in every 10 at Dartmouth.
• Patients who had a primary care visit within a year were nearly 5 times more likely to be screened.
• Those who lived in a zip code with median household income ≤$52,000 were 21% less likely to be screened.
• Medicaid patients were 28% less likely to be screened; Medicare and uninsured patients were 45% and 65% less likely to do so, respectively.