Figure 3
Parity and mammographic density. Least square means of percentage mammographic density according to number of live births, adjusted for age, body mass index, age at menarche, age at first birth, menopausal status, age at menopause, previous use of menopausal hormone therapy (ever/never) and breast cancer in first degree relatives (0, 1, 2+). The height of the bar is the least square mean of percentage density, and half width of the error bar represents the standard error. Data from Boyd and coworkers [4].