Table 2.

Density Prevalence by Age

	Distribution of BI-RADS Breast Density Categories
Age	Almost Entirely Fatty	Scattered Fibroglandular Densities	Heterogeneously Dense	Extremely Dense
40–44 years	8%	36%	44%	13%
45–49 years	8%	37%	43%	12%
50–54 years	12%	42%	38%	8%
55–59 years	15%	47%	33%	5%
60–64 years	18%	49%	29%	4%
65–69 years	18%	50%	28%	3%
70–74 years	20%	53%	24%	2%
75–79 years	20%	53%	25%	3%
80–84 years	18%	54%	26%	2%
85+ years	19%	54%	25%	3%

Adapted from Sprague BL, Gangnon RE, Trentham-Dietz A, et al. Prevalence of mammographically dense breasts in the United States. J Natl Cancer Inst 2014; 106(10):dju255; with permission.