Table 3

ORs and 95% CIs for breast cancer associated with mammographic density by ethnic group

DensityCasesControlsUnadjusted ORAdjusted ORaAdjusted 95% CIa
Percent density
All womenb
 <121351.001.00Referent
 1-64711.501.570.81–3.03
 10-100881.891.740.91–3.31
 25-2471612.562.301.24–4.28
 50-170823.463.211.65–6.25
 ≥752065.565.231.70–16.13
Ptrend = 0.0001c
Per 10%1.151.07–1.23
White
 <1037571.001.00Referent
 10–591891471.981.570.93–2.63
 ≥6054233.622.561.23–5.31
Ptrend = 0.01c
Per 10%1.151.04–1.27
African American
 <1039421.001.00Referent
 10–59138941.581.440.81–2.58
 ≥6022131.821.660.64–4.32
Ptrend = 0.22c
Per 10%1.110.98–1.26
Asian American
 <10971.001.00Referent
 10–59108521.623.070.80–11.77
 ≥602682.536.421.23–33.48
Ptrend = 0.03c
Per 10%1.301.05–1.61
Test of effect modification by ethnic group P = 0.77a
Absolute density (pixels)b
All Women
08161.001.00Referent
>0-89971.841.860.73–4.74
50,000-105852.472.050.79–5.32
100,000-2221413.152.641.04–6.69
200,000-117623.773.301.27–8.61
300,000-81423.863.801.43–10.08
846,970Ptrend = 0.0001c
Per decile1.161.06–1.27
Absolute density (tertiles)d
White
 First68921.001.00Referent
 Second113742.071.771.12–2.79
 Third99612.201.851.14–2.99
Ptrend = 0.01c
Per decile1.181.02–1.36
African American
 First58581.001.00Referent
 Second56391.441.280.72–2.30
 Third85521.641.530.89–2.63
Ptrend = 0.13c
Per decile1.090.96–1.25
Asian American
 First50291.001.00Referent
 Second48251.111.140.51–2.54
 Third45132.012.931.23–6.95
Ptrend = 0.02c
Per decile1.431.07–1.93
Test of effect modification by ethnic group P = 0.56a
  • a Adjusted for age at mammography, BMI, age at menarche, breast cancer family history, number of full-term pregnancies, menopausal status and HRT use, and age at first full-term pregnancy.

  • b Also adjusted for ethnicity.

  • c P for trend test is based on Wald statistic and is two-sided.

  • d Tertile cutpoints are 91,500 and 177,600 pixels.