From: Mammographic density. Potential mechanisms of breast cancer risk associated with mammographic density: hypotheses based on epidemiological evidence
Quintiles of percentage density
1
2
3
4
5
P value for trend
Premenopausal (n = 160)
2.76a
2.29
2.86
2.75
3.62
0.02
Postmenopausal (n = 175)
3.19
3.23
3.67
3.46
3.88
0.13
All women (n = 335)
3.02
2.76
3.10
3.38
3.68
0.01