Changes in mammographic density over time and the risk of breast cancer: An observational cohort study

Background The effect of changes in mammographic density over time on the risk of breast cancer remains inconclusive. Methods We used information from four centres of the Breast Cancer Screening Program in Spain in the period 1996–2015. We analysed individual level data from 117,388 women first screened age 50–54, with at least two screening examinations. Breast density was determined using the BI-RADS classification (A to D in increasing order)...