Having higher density breasts means that your breasts have more tissue than fat. Breast density is assessed with mammogramy.
Studies consistently have found that, as breast density increases, so does the risk of breast cancer. Women with higher breast density are 4 to 6 times more likely to develop breast cancer than are women with lower density breasts (breasts with a much greater proportion of fat than tissue).
Remember that breast density is one of many small factors contributing to breast cancer risk. Having high-density breasts is not something to fret about.