Table 2 Calculation of cumulative percent mammographic density
From: The origins of breast cancer associated with mammographic density: a testable biological hypothesis
Age (years) | No. of subjects | Median calibrated percent watera | Median percent dense area | Years | Calibrated breast density years | Calibrated cumulative breast density years |
|---|---|---|---|---|---|---|
15–19 | 974 | 51.7 |  | 5 | 258.5 | 258.6 |
20–24 | 86 | 46.5 |  | 5 | 232.5 | 491.1 |
25–29 | 83 | 47.0 |  | 5 | 235.0 | 726.1 |
30–34 | 15 | 46.3 |  | 5 | 231.5 | 957.6 |
35–39 | 49 |  | 45.9 | 5 | 229.6 | 1187.3 |
40–44 | 405 |  | 40.4 | 5 | 202.0 | 1389.3 |
45–49 | 654 |  | 37.3 | 5 | 186.6 | 1575.9 |
50–54 | 789 |  | 28.4 | 5 | 141.9 | 1717.8 |
55–59 | 546 |  | 23.8 | 5 | 119.0 | 1836.9 |
60–64 | 324 |  | 23.1 | 5 | 115.3 | 1952.2 |
65–69 | 259 |  | 19.2 | 5 | 96.1 | 2048.3 |
70–74 | 171 |  | 18.5 | 5 | 92.5 | 2140.8 |
75–79 | 76 |  | 18.3 | 5 | 91.3 | 2232.1 |
80+ | 23 | Â | 15.2 | 5 | 76.0 | 2308.1 |