1. A method of assessing breast density for breast cancer risk applications, the method comprising: receiving digital image data including a plurality of pixels; calibrating the digital image data, wherein each pixel is mapped into a normalized percent glandular representation; performing a statistical analysis with optimization on the calibrated digital image data, by; determining measured characteristics of the calibrated image or the digital image data based on a deviation of the pixel values within a breast region; and determining four-state breast density variables based on the determined measured characteristics by applying an optimization, wherein the optimization comprises maximizing or minimizing a fitness function by a repeated processing of case-control data with plural random vectors for a given breast density measurement determination for a number of generations, wherein the number of generations is less than predetermined value when a preset convergence condition is met; and associating the statistically analyzed digital image data with a measure of risk for breast cancer.